How Much Acid Is Needed For Start Up Period?

[HouTex1962]

Hi, I'm new to the forum. This forum was very helpful during our construction phase--I had to finish my pool without my PB--but that's another story. I appreciate everyone's input.

Our pool was filled with water on 12/4/2010 (approx. 9,200 gallons) and is finished with Wet Edge Luna Quartz French Grey. The water turned blue in a couple of days and looks great. The chlorine level has been good and the ph, as expected, has ranged from 7.8 to 8.2 (before adding acid each day). Alkalinity is within the recommended range. I have added a gallon of acid each day since start up which takes the ph down to around 6.8 by the end of the day. By the next morning the ph is back up to 7.8 to 8.2 My plaster company's instructions said to keep the ph between 6.6 and 7.0 for the first week and shoot for 7.2 to 7.4 thereafter. So far I've added 6 gallons of acid. About how long can I expect this to go on, understanding that every pool is different?

[edit] The pool is a chlorine pool.

[waterbear]

Hi, I'm new to the forum. This forum was very helpful during our construction phase--I had to finish my pool without my PB--but that's another story. I appreciate everyone's input.

Our pool was filled with water on 12/4/2010 (approx. 9,200 gallons) and is finished with Wet Edge Luna Quartz French Grey. The water turned blue in a couple of days and looks great. The chlorine level has been good and the ph, as expected, has ranged from 7.8 to 8.2 (before adding acid each day). Alkalinity is within the recommended range. I have added a gallon of acid each day since start up which takes the ph down to around 6.8 by the end of the day. By the next morning the ph is back up to 7.8 to 8.2 My plaster company's instructions said to keep the ph between 6.6 and 7.0 for the first week and shoot for 7.2 to 7.4 thereafter. So far I've added 6 gallons of acid. About how long can I expect this to go on, understanding that every pool is different?

[edit] The pool is a chlorine pool.

Expect to go through a LOT of acid during startup and curing. This usually means during the first 6 months to year. The amount needed will gradually decrease. I would strongly recommend getting a GOOD test kit that has an acid demand test. My recommendation would be the Taylor K-2006 (not the K-2005) because it also has a superior chlorine test. This will make the task of keeping your water in balance a no brainer.

Wet Edge Luna Quartz is an exposed aggregate finish, which is why they are having you keep the pH low for the first week. This is what exposes the aggregate (by etching away the plaster).

What is the actual measurement of your TA? Three things to realize about TA and pH:

The lower you put the pH the faster it will rise (because of faster outgasing of CO2).

The higher the TA the fast pH will rise (because of higher carbonation of the water).

Aeration of the water increases outgassing of CO2 and, therefore, pH rise.

Where you keep the TA depends more on what type of chlorine you use and how much aeration the pool gets than anything else.

However, with new plaster you are also dealing with alkaline substances being 'shed' by the plaster into the water by the chemical process of the plaster curing. This creates additional acid demand. Once the plaster is cured, which often takes up to a year, the above three "rules" take over and the primary cause of pH rise (acid demand) is outgassing of CO2 from the water.

One final note:

"good" is not a chlorine measurement and "within the recommended range" is not a TA measurement. If you want relevant advice then we need full test results so we know what is going on in your water. With new plaster we also would need to know your calcium hardness and, as far as TA goes, how you are chlorinating since stabilized chlorine does need a higher TA than unstabilized chlorine because stabilized chlorine produces have a net acidic effect on pool water while unstabilized chlorine sources are nearly pH neutral. (I am not talking about the actual pH of the chlorine product but on their total effect on pool water.)

In fact, if you are not chlorinating with trichlor then you might want to consider it during the start up and curing of your plaster since it will help keep the pH in line because it is extremely acidic. However, if you go this route keep close watch on your CYA readings, expeically if you have a cartridge filter, since stabilized chlorine products will cause your CYA levels to keep rising and lead to overstabilization.

Hope this helps.

[HouTex1962]

Hi, I'm new to the forum. This forum was very helpful during our construction phase--I had to finish my pool without my PB--but that's another story. I appreciate everyone's input.

Our pool was filled with water on 12/4/2010 (approx. 9,200 gallons) and is finished with Wet Edge Luna Quartz French Grey. The water turned blue in a couple of days and looks great. The chlorine level has been good and the ph, as expected, has ranged from 7.8 to 8.2 (before adding acid each day). Alkalinity is within the recommended range. I have added a gallon of acid each day since start up which takes the ph down to around 6.8 by the end of the day. By the next morning the ph is back up to 7.8 to 8.2 My plaster company's instructions said to keep the ph between 6.6 and 7.0 for the first week and shoot for 7.2 to 7.4 thereafter. So far I've added 6 gallons of acid. About how long can I expect this to go on, understanding that every pool is different?

[edit] The pool is a chlorine pool.

Expect to go through a LOT of acid during startup and curing. This usually means during the first 6 months to year. The amount needed will gradually decrease. I would strongly recommend getting a GOOD test kit that has an acid demand test. My recommendation would be the Taylor K-2006 (not the K-2005) because it also has a superior chlorine test. This will make the task of keeping your water in balance a no brainer.

Wet Edge Luna Quartz is an exposed aggregate finish, which is why they are having you keep the pH low for the first week. This is what exposes the aggregate (by etching away the plaster).

What is the actual measurement of your TA? Three things to realize about TA and pH:

The lower you put the pH the faster it will rise (because of faster outgasing of CO2).

The higher the TA the fast pH will rise (because of higher carbonation of the water).

Aeration of the water increases outgassing of CO2 and, therefore, pH rise.

Where you keep the TA depends more on what type of chlorine you use and how much aeration the pool gets than anything else.

However, with new plaster you are also dealing with alkaline substances being 'shed' by the plaster into the water by the chemical process of the plaster curing. This creates additional acid demand. Once the plaster is cured, which often takes up to a year, the above three "rules" take over and the primary cause of pH rise (acid demand) is outgassing of CO2 from the water.

One final note:

"good" is not a chlorine measurement and "within the recommended range" is not a TA measurement. If you want relevant advice then we need full test results so we know what is going on in your water. With new plaster we also would need to know your calcium hardness and, as far as TA goes, how you are chlorinating since stabilized chlorine does need a higher TA than unstabilized chlorine because stabilized chlorine produces have a net acidic effect on pool water while unstabilized chlorine sources are nearly pH neutral. (I am not talking about the actual pH of the chlorine product but on their total effect on pool water.)

In fact, if you are not chlorinating with trichlor then you might want to consider it during the start up and curing of your plaster since it will help keep the pH in line because it is extremely acidic. However, if you go this route keep close watch on your CYA readings, expeically if you have a cartridge filter, since stabilized chlorine products will cause your CYA levels to keep rising and lead to overstabilization.

Hope this helps.

Thanks for your reply. Here's a little more information. I'm using 3" trichlor tablets through an inline feeder. I also have a cartridge filter. My test kit (a cheap one) has been showing 2.0 ppm consistently and that level was confirmed by my pool supply store. Their test also confirmed the ph results of my test kit. Their tests showed that TA was 85 and CYA was zero. I've been planning to add CYA as soon as the ph stabilizes. I forget the number, but the water hardness was very low. The people at the pool supply store just said to keep adding muriatic acid until the ph stabilizes then we'd worry about water hardness and CYA levels. I also haven't shocked the pool yet--they said there was no need to because of the 2.0 free chlorine level and because the water had cleared. Again, thanks for your input.

[quantumchromodynamics]

When I start up a plaster pool, I don't use very much acid at all. Usually just a few gallons in the first few weeks and that's it. Your aggressive chemistry is dissolving the plaster and causing the pH rise. If you get your CSI up to near zero, your acid usage should drop significantly.

I recommend that you keep the pH at about 7.6 to 7.9. Increase your cyanuric acid to about 40 ppm and increase your calcium enough to get your CSI to about -0.1.

Brush the pool daily to remove any plaster dust.

The Langelier Saturation Index (LSI) must be maintained between 0.0 and +0.3 for day-to-day maintenance after the initial start up procedure has been completed. This will help to reduce the likelihood of problems with the pool surface. Disregarding these LSI parameters promotes leaching, etching and discoloration on the negative (-) side and scaling and discoloration on the positive (+) side.

http://www.npconline.net/StartUp.pdf

[HouTex1962]

When I start up a plaster pool, I don't use very much acid at all. Usually just a few gallons in the first few weeks and that's it. Your aggressive chemistry is dissolving the plaster and causing the pH rise. If you get your CSI up to near zero, your acid usage should drop significantly.

I recommend that you keep the pH at about 7.6 to 7.9. Increase your cyanuric acid to about 40 ppm and increase your calcium enough to get your CSI to about -0.1.

Brush the pool daily to remove any plaster dust.

http://www.npconline.net/StartUp.pdf

Thanks. I've been brushing every day (with a wire brush) as instructed by my Luna Quartz installer. This morning the dust was almost gone. Your recommended ph is much higher than what Wet Edge and my plaster installer recommends.

[edit] I should clarify that my TA and CYA readings above (85 and zero, respectively) were taken at the same time that ph registered 6.8--which was about 9 hours after adding 1 gallon of acid. Just to be clear, the ph each morning before I add acid has ranged from 7.8 up to about 8.2.

[quantumchromodynamics]

The NPC (National Plasterer's Council) startup procedure that I referenced above recommends a pH of between 7.2 and 7.6. I find that a pH of 7.7 to 7.9 works well as long as the CSI does not get too high.

I think that the combination of the wire brush and the low CSI is too aggressive and is causing unnecessary plaster wear and pH increase. I think that you can increase the CSI to at least -0.3 and start using a nylon bristle brush.

[quantumchromodynamics]

Here are the recommendations from wet edge:

Recommended Pool Water Chemistry Guidelines

pH 7.0 to 7.4

Alkalinity 70 to 90 ppm

Calcium Hardness 180 ppm

Chlorine Level 0.5 to 1.5 ppm

Recommended Water Balance after the Start Up

pH 7.4 to 7.6

Alkalinity 80 to 120 ppm

Chlorine Level 1 to 3 ppm

Calcium Hardness 200 to 400 ppm

Cyanuric acid below 50 ppm

http://www.wetedgetechnologies.com/pdfs/StartUp_Altima_Gray.pdf

I think that if you want to keep within their guidelines, you should aim for a pH of 7.4. I think that less than that is too aggressive. Increasing the calcium to 180 should help as well.

[HouTex1962]

The NPC (National Plasterer's Council) startup procedure that I referenced above recommends a pH of between 7.2 and 7.6. I find that a pH of 7.7 to 7.9 works well as long as the CSI does not get too high.

I think that the combination of the wire brush and the low CSI is too aggressive and is causing unnecessary plaster wear and pH increase. I think that you can increase the CSI to at least -0.3 and start using a nylon bristle brush.

Thanks, I appreciate your input. Note that the instructions I was given by my plaster installer (which appear to be from Wet Edge) called for a wire brush for the life of the pool for exposed aggregate finishes like Luna Quartz. After tomorrow (the 7th day) the recommendation is to brush the pool once a week.

[HouTex1962]

Here are the recommendations from wet edge:

Recommended Pool Water Chemistry Guidelines

pH 7.0 to 7.4

Alkalinity 70 to 90 ppm

Calcium Hardness 180 ppm

Chlorine Level 0.5 to 1.5 ppm

Recommended Water Balance after the Start Up

pH 7.4 to 7.6

Alkalinity 80 to 120 ppm

Chlorine Level 1 to 3 ppm

Calcium Hardness 200 to 400 ppm

Cyanuric acid below 50 ppm

http://www.wetedgetechnologies.com/pdfs/StartUp_Altima_Gray.pdf

I think that if you want to keep within their guidelines, you should aim for a pH of 7.4. I think that less than that is too aggressive. Increasing the calcium to 180 should help as well.

For some reason my plaster installer crossed out 7.4-7.6 for the recommended post-start up ph and hand wrote "7.2-7.4" for the recommended ph. I can only assume that they did that with Wet Edge's blessing. For what it's worth, I think my plaster guy is a good guy and did a great job. I can't imagine him making that change without Wet Edge's approval. In any event, your recommendation of 7.4 is ok with either approach. I'll shoot for that. I may try adding acid in lower amounts, i.e. not a gallon at a time, to avoid the spikes I'm getting.

But I still wonder how many gallons of acid it will take before the ph stabilizes. Any general idea?

[quantumchromodynamics]

It's going to depend on how aggressive your water is. The way I start up a pool, I only need about 1 gallon of acid per 10,000 gallons of pool water in the first two or three weeks. After that, I don't usually need any acid.

Increasing your target pH and CSI should begin to significantly reduce your need for acid, especially if you're using trichlor.

DO Use a combo pool brush (steel/nylon)

Reference

The above source specifies a combo stainless steel/Nylon brush. I think that an all nylon brush should be sufficient.

[waterbear]

Here are the recommendations from wet edge:

Recommended Pool Water Chemistry Guidelines

pH 7.0 to 7.4

Alkalinity 70 to 90 ppm

Calcium Hardness 180 ppm

Chlorine Level 0.5 to 1.5 ppm

Recommended Water Balance after the Start Up

pH 7.4 to 7.6

Alkalinity 80 to 120 ppm

Chlorine Level 1 to 3 ppm

Calcium Hardness 200 to 400 ppm

Cyanuric acid below 50 ppm

http://www.wetedgete...Altima_Gray.pdf

I think that if you want to keep within their guidelines, you should aim for a pH of 7.4. I think that less than that is too aggressive. Increasing the calcium to 180 should help as well.

For some reason my plaster installer crossed out 7.4-7.6 for the recommended post-start up ph and hand wrote "7.2-7.4" for the recommended ph. I can only assume that they did that with Wet Edge's blessing. For what it's worth, I think my plaster guy is a good guy and did a great job. I can't imagine him making that change without Wet Edge's approval. In any event, your recommendation of 7.4 is ok with either approach. I'll shoot for that. I may try adding acid in lower amounts, i.e. not a gallon at a time, to avoid the spikes I'm getting.

But I still wonder how many gallons of acid it will take before the ph stabilizes. Any general idea?

It sounds like your plasterer wanted the lower pH to remove more of the plaster to expose the aggregate. Perhaos they dod not clean it well when they did the initial acid wash.

There are actually three ways to start a new plaster pool:

Standard startup, which seems to be what you are doing more or less.

Acid startup, which really should only be done by an experience professional but is often used with exposed aggregate finishes since it eliminates the acid wash step.

Bicarbonate startup, which produces an excellent finish on plain plaster but is probably not as useful for aggregate finishes.

[HouTex1962]

Here are the recommendations from wet edge:

Recommended Pool Water Chemistry Guidelines

pH 7.0 to 7.4

Alkalinity 70 to 90 ppm

Calcium Hardness 180 ppm

Chlorine Level 0.5 to 1.5 ppm

Recommended Water Balance after the Start Up

pH 7.4 to 7.6

Alkalinity 80 to 120 ppm

Chlorine Level 1 to 3 ppm

Calcium Hardness 200 to 400 ppm

Cyanuric acid below 50 ppm

http://www.wetedgete...Altima_Gray.pdf

I think that if you want to keep within their guidelines, you should aim for a pH of 7.4. I think that less than that is too aggressive. Increasing the calcium to 180 should help as well.

For some reason my plaster installer crossed out 7.4-7.6 for the recommended post-start up ph and hand wrote "7.2-7.4" for the recommended ph. I can only assume that they did that with Wet Edge's blessing. For what it's worth, I think my plaster guy is a good guy and did a great job. I can't imagine him making that change without Wet Edge's approval. In any event, your recommendation of 7.4 is ok with either approach. I'll shoot for that. I may try adding acid in lower amounts, i.e. not a gallon at a time, to avoid the spikes I'm getting.

But I still wonder how many gallons of acid it will take before the ph stabilizes. Any general idea?

It sounds like your plasterer wanted the lower pH to remove more of the plaster to expose the aggregate. Perhaos they dod not clean it well when they did the initial acid wash.

There are actually three ways to start a new plaster pool:

Standard startup, which seems to be what you are doing more or less.

Acid startup, which really should only be done by an experience professional but is often used with exposed aggregate finishes since it eliminates the acid wash step.

Bicarbonate startup, which produces an excellent finish on plain plaster but is probably not as useful for aggregate finishes.

After adding the gallon of acid yesterday morning by evening time my ph was lower than 6.8 (the lowest reading on my test kit). By this morning it was up to 7.2 which is the best reading thus far. The other days the ph was over 7.8 after 24 hours of adding a gallon of acid. I will not add acid until the ph exceeds 7.4 and then only about a quart at a time.

[quantumchromodynamics]

Plaster dust is caused by calcium hydroxide, which forms during the curing of the cement. The calcium hydroxide combines with the bicarbonate to form calcium carbonate.

Ca(OH)₂ + HCO₃^- < > CaCO₃ + H₂O + OH^-

The top layer of plaster should have most of the calcium hydroxide convert into calcium carbonate. If your water chemistry is too aggressive, then the plaster won't be able to form a passivation layer of calcium carbonate. As you go deeper into the plaster, you will expose more calcium hydroxide and the plaster will continue to dissolve. The bicarbonate startup procedure provides extra bicarbonate to help convert the calcium hydroxide to calcium carbonate.

Since your aggregate is quartz, some of the calcium hydroxide should become calcium silicate, which is less susceptible to dissolution by aggressive water.

Note: The most important factor is the CSI when determining the risk of scaling or etching. My recommendation for a higher pH is offset by a lower calcium and TA level. By increasing the pH and lowering the TA, you will get less pH increase due to carbon dioxide off-gassing.

The wetedge startup guide does not address CSI. That's one of the reasons that they use a lower figure for the pH

You can use the pool calculator to calculate your CSI (Calcite Saturation Index). I recommend that you keep the CSI at about -0.2 to -0.1 for the first 28 days and then at 0.0 to +0.3 after the first 28 days.

[HouTex1962]

Plaster dust is caused by calcium hydroxide, which forms during the curing of the cement. The calcium hydroxide combines with the bicarbonate to form calcium carbonate.

Ca(OH)₂ + HCO₃^- < > CaCO₃ + H₂O + OH^-

The top layer of plaster should have most of the calcium hydroxide convert into calcium carbonate. If your water chemistry is too aggressive, then the plaster won't be able to form a passivation layer of calcium carbonate. As you go deeper into the plaster, you will expose more calcium hydroxide and the plaster will continue to dissolve. The bicarbonate startup procedure provides extra bicarbonate to help convert the calcium hydroxide to calcium carbonate.

Since your aggregate is quartz, some of the calcium hydroxide should become calcium silicate, which is less susceptible to dissolution by aggressive water.

Note: The most important factor is the CSI when determining the risk of scaling or etching. My recommendation for a higher pH is offset by a lower calcium and TA level. By increasing the pH and lowering the TA, you will get less pH increase due to carbon dioxide off-gassing.

The wetedge startup guide does not address CSI. That's one of the reasons that they use a lower figure for the pH

You can use the pool calculator to calculate your CSI (Calcite Saturation Index). I recommend that you keep the CSI at about -0.2 to -0.1 for the first 28 days and then at 0.0 to +0.3 after the first 28 days.

UPDATE: It's been almost two months since start up and the ph has stabilized dramatically. I still need to add acid but it's down to about 16 oz. or so every second or third day. Here are my readings: FC 2.0, CC 0.0, pH 7.6, Hardness 375, TA 65, CYA 65, Total dissolved solids 1200. I'm adding baking soda to get the TA up to the 90-100 range. As far as looks, the pool water could not look better.

[PoolGuyNJ]

I'm reading this for the first time and saw a couple things:

Don't brush with a wire brush, use a regular pool brush at startup. It sounds like the plaster guy did a water wash vs. and acid wash prior to filling, hence the low pH startup.

With TriChlor tabs, stabilizer is being added with the tabs. Slowly, granted but it will continue to increase. CYA doesn't evaporate with the water, it stays in.

Your current stabilizer level should dictate your FC level, typically 10% of the CYA level when using tabs or bleach/liquid. That means for FC to be effective, you will need an FC of about 7 once the water gets above 65 degrees F. or you will get algae and other bio-badies.

Scott

[HouTex1962]

Then it would seem that the CYA should never get that high in the first place. I've never added any stabalizer. The CYA in the pool is what comes with the Trichlor. With a chlorine pool, what choices do you really have so that CYA does not continue to increase? Should I be using plain clorox every other day or so?

[chem geek]

The following are chemical facts that are independent of concentration of product or of pool size:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.

For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.

For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.

So with 2 ppm FC per day chlorine usage, the CYA would build up by 36 ppm per month. Even at only 1 ppm FC per day usage, after 6 months that's over 100 ppm CYA if there were no water dilution.

Yes, you can use chlorinating liquid or bleach to add chlorine without CYA or CH. Read the Pool School for more info on how you can maintain your pool free of algae without spending any money on algaecides, clarifiers, flocculants, phosphate removers, enzymes, etc. I use only 12.5% chlorinating liquid in my 16,000 gallon pool (shown ) added about twice a week plus a small amount of acid about once a month that costs me $15 per month. Now I have a rather low 1 ppm FC per day chlorine usage because I have a mostly opaque pool cover, though the pool is used every day for 1-2 hours during the week and longer on weekends.

The downside to chlorinating liquid or 6% unscented bleach is that you need to add it every day or two unless you have low chlorine usage by keeping sun off the pool. There are ways around this including automatic dosing systems such as The Liquidator or use of a peristaltic pump or using a saltwater chlorine generator.

[HouTex1962]

The following are chemical facts that are independent of concentration of product or of pool size:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.

For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.

For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.

So with 2 ppm FC per day chlorine usage, the CYA would build up by 36 ppm per month. Even at only 1 ppm FC per day usage, after 6 months that's over 100 ppm CYA if there were no water dilution.

Yes, you can use chlorinating liquid or bleach to add chlorine without CYA or CH. Read the Pool School for more info on how you can maintain your pool free of algae without spending any money on algaecides, clarifiers, flocculants, phosphate removers, enzymes, etc. I use only 12.5% chlorinating liquid in my 16,000 gallon pool (shown ) added about twice a week plus a small amount of acid about once a month that costs me $15 per month. Now I have a rather low 1 ppm FC per day chlorine usage because I have a mostly opaque pool cover, though the pool is used every day for 1-2 hours during the week and longer on weekends.

The downside to chlorinating liquid or 6% unscented bleach is that you need to add it every day or two unless you have low chlorine usage by keeping sun off the pool. There are ways around this including automatic dosing systems such as The Liquidator or use of a peristaltic pump or using a saltwater chlorine generator.

Thanks for the input. I guess I should have done a little more research before we went with a chlorine system. We were going to install a SWG at first, but after hearing about some problems with green water and the need to continually add acid as well as other issues, we decided to go with a chlorine pool. I still may convert to a SWG if the CYA becomes a problem.

But what I don't get is that my family always had a pool growing up and it was always in great shape as far as water clarity was concerned and it never had an algae problem. My father did everything himself and he used chlorine sticks which must have had CYA (this was in the mid-70s to mid-80s)in them. I never recall that he had to drain any water to lower CYA and I don't even remember that he even tested for CYA. Pretty much all he did was make sure the pH was in range and that FC was in the 1-3 range. And he shocked the pool with a product called "Burn Out," as I recall, after a pool party. And that was it and the pool always looked great.

[waterbear]

The following are chemical facts that are independent of concentration of product or of pool size:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.

For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.

For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.

So with 2 ppm FC per day chlorine usage, the CYA would build up by 36 ppm per month. Even at only 1 ppm FC per day usage, after 6 months that's over 100 ppm CYA if there were no water dilution.

Yes, you can use chlorinating liquid or bleach to add chlorine without CYA or CH. Read the Pool School for more info on how you can maintain your pool free of algae without spending any money on algaecides, clarifiers, flocculants, phosphate removers, enzymes, etc. I use only 12.5% chlorinating liquid in my 16,000 gallon pool (shown ) added about twice a week plus a small amount of acid about once a month that costs me $15 per month. Now I have a rather low 1 ppm FC per day chlorine usage because I have a mostly opaque pool cover, though the pool is used every day for 1-2 hours during the week and longer on weekends.

The downside to chlorinating liquid or 6% unscented bleach is that you need to add it every day or two unless you have low chlorine usage by keeping sun off the pool. There are ways around this including automatic dosing systems such as The Liquidator or use of a peristaltic pump or using a saltwater chlorine generator.

Thanks for the input. I guess I should have done a little more research before we went with a chlorine system. We were going to install a SWG at first, but after hearing about some problems with green water and the need to continually add acid as well as other issues, we decided to go with a chlorine pool. I still may convert to a SWG if the CYA becomes a problem.

But what I don't get is that my family always had a pool growing up and it was always in great shape as far as water clarity was concerned and it never had an algae problem. My father did everything himself and he used chlorine sticks which must have had CYA (this was in the mid-70s to mid-80s)in them. I never recall that he had to drain any water to lower CYA and I don't even remember that he even tested for CYA. Pretty much all he did was make sure the pH was in range and that FC was in the 1-3 range. And he shocked the pool with a product called "Burn Out," as I recall, after a pool party. And that was it and the pool always looked great.

Burn out is cal hypo, an unstabilized chlorine source. How often did he have to add algaecide and did you live in a climate that required winterizing. Also, I will bet yo had a sand filter. All these are factors that can make trichlor work in a pool (short swim season, winterizing and backwashing). However, if you live in a climate with a longer swim season and have a cart filter or large capacity DE filter and you don't winterize then the use of trichlor and dichlor wan and will lead to an overstabilized pool in a matter of months and will require special measure to keep it from turning green such as the addition of algaecides (which impart their own set of problems) or periodic drain and fills.

FWIW a salt system IS a chlorine system. It's just a way to automatically add unstabilized chlorine to your pool. If the chlorine is maintained properly the pool won't turn green. It's usually a pool on trichlor that turns green. As far as acid use, that can be minimized by proper water balance. Trichlor is extremely acidic, which is why it does not require acid BUT it does require constant monitoring of both pH and TA because it depletes TA and when that happens pH can crash dangerously low so you need to keep adding soda ash, bicarbonate, and/or borax on a regular basis instead of acid. six of one, half a dozen of the other.

[waterbear]

The following are chemical facts that are independent of concentration of product or of pool size:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.

For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.

For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.

So with 2 ppm FC per day chlorine usage, the CYA would build up by 36 ppm per month. Even at only 1 ppm FC per day usage, after 6 months that's over 100 ppm CYA if there were no water dilution.

Yes, you can use chlorinating liquid or bleach to add chlorine without CYA or CH. Read the Pool School for more info on how you can maintain your pool free of algae without spending any money on algaecides, clarifiers, flocculants, phosphate removers, enzymes, etc. I use only 12.5% chlorinating liquid in my 16,000 gallon pool (shown ) added about twice a week plus a small amount of acid about once a month that costs me $15 per month. Now I have a rather low 1 ppm FC per day chlorine usage because I have a mostly opaque pool cover, though the pool is used every day for 1-2 hours during the week and longer on weekends.

The downside to chlorinating liquid or 6% unscented bleach is that you need to add it every day or two unless you have low chlorine usage by keeping sun off the pool. There are ways around this including automatic dosing systems such as The Liquidator or use of a peristaltic pump or using a saltwater chlorine generator.

Thanks for the input. I guess I should have done a little more research before we went with a chlorine system. We were going to install a SWG at first, but after hearing about some problems with green water and the need to continually add acid as well as other issues, we decided to go with a chlorine pool. I still may convert to a SWG if the CYA becomes a problem.

But what I don't get is that my family always had a pool growing up and it was always in great shape as far as water clarity was concerned and it never had an algae problem. My father did everything himself and he used chlorine sticks which must have had CYA (this was in the mid-70s to mid-80s)in them. I never recall that he had to drain any water to lower CYA and I don't even remember that he even tested for CYA. Pretty much all he did was make sure the pH was in range and that FC was in the 1-3 range. And he shocked the pool with a product called "Burn Out," as I recall, after a pool party. And that was it and the pool always looked great.

Burn out is cal hypo, an unstabilized chlorine source. How often did he have to add algaecide and did you live in a climate that required winterizing. Also, I will bet yo had a sand filter. All these are factors that can make trichlor work in a pool (short swim season, winterizing and backwashing). However, if you live in a climate with a longer swim season and have a cart filter or large capacity DE filter and you don't winterize then the use of trichlor and dichlor wan and will lead to an overstabilized pool in a matter of months and will require special measure to keep it from turning green such as the addition of algaecides (which impart their own set of problems) or periodic drain and fills.

Also, Burnout is made by Bioguard and I bet as are the sticks of trichlor your Dad used. Bioguard is a Chemtura brand and they are a major trichlor manufacturer. Their coperate stance for all their brands (which include Guardex, Omni, Sun, AquaChem, and Pool Time, among others) is that CYA doesn't matter since it would cut into their corporate profits if the truth were better known and also cut into their sales of algaecides, very expensive borax (Optimizer and Maximizer), and very expensive baking soda (which they label as sodium hydrogen carbonate instead of sodium bicarbonate so it looks like something special when it is just another name for the same exact thing you buy at the grocery!)

FWIW a salt system IS a chlorine system. It's just a way to automatically add unstabilized chlorine to your pool. If the chlorine is maintained properly the pool won't turn green. It's usually a pool on trichlor that turns green. As far as acid use, that can be minimized by proper water balance. Trichlor is extremely acidic, which is why it does not require acid BUT it does require constant monitoring of both pH and TA because it depletes TA and when that happens pH can crash dangerously low so you need to keep adding soda ash, bicarbonate, and/or borax on a regular basis instead of acid. six of one, half a dozen of the other.

[HouTex1962]

The following are chemical facts that are independent of concentration of product or of pool size:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.

For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.

For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.

So with 2 ppm FC per day chlorine usage, the CYA would build up by 36 ppm per month. Even at only 1 ppm FC per day usage, after 6 months that's over 100 ppm CYA if there were no water dilution.

Yes, you can use chlorinating liquid or bleach to add chlorine without CYA or CH. Read the Pool School for more info on how you can maintain your pool free of algae without spending any money on algaecides, clarifiers, flocculants, phosphate removers, enzymes, etc. I use only 12.5% chlorinating liquid in my 16,000 gallon pool (shown ) added about twice a week plus a small amount of acid about once a month that costs me $15 per month. Now I have a rather low 1 ppm FC per day chlorine usage because I have a mostly opaque pool cover, though the pool is used every day for 1-2 hours during the week and longer on weekends.

The downside to chlorinating liquid or 6% unscented bleach is that you need to add it every day or two unless you have low chlorine usage by keeping sun off the pool. There are ways around this including automatic dosing systems such as The Liquidator or use of a peristaltic pump or using a saltwater chlorine generator.

Thanks for the input. I guess I should have done a little more research before we went with a chlorine system. We were going to install a SWG at first, but after hearing about some problems with green water and the need to continually add acid as well as other issues, we decided to go with a chlorine pool. I still may convert to a SWG if the CYA becomes a problem.

But what I don't get is that my family always had a pool growing up and it was always in great shape as far as water clarity was concerned and it never had an algae problem. My father did everything himself and he used chlorine sticks which must have had CYA (this was in the mid-70s to mid-80s)in them. I never recall that he had to drain any water to lower CYA and I don't even remember that he even tested for CYA. Pretty much all he did was make sure the pH was in range and that FC was in the 1-3 range. And he shocked the pool with a product called "Burn Out," as I recall, after a pool party. And that was it and the pool always looked great.

Burn out is cal hypo, an unstabilized chlorine source. How often did he have to add algaecide and did you live in a climate that required winterizing. Also, I will bet yo had a sand filter. All these are factors that can make trichlor work in a pool (short swim season, winterizing and backwashing). However, if you live in a climate with a longer swim season and have a cart filter or large capacity DE filter and you don't winterize then the use of trichlor and dichlor wan and will lead to an overstabilized pool in a matter of months and will require special measure to keep it from turning green such as the addition of algaecides (which impart their own set of problems) or periodic drain and fills.

Also, Burnout is made by Bioguard and I bet as are the sticks of trichlor your Dad used. Bioguard is a Chemtura brand and they are a major trichlor manufacturer. Their coperate stance for all their brands (which include Guardex, Omni, Sun, AquaChem, and Pool Time, among others) is that CYA doesn't matter since it would cut into their corporate profits if the truth were better known and also cut into their sales of algaecides, very expensive borax (Optimizer and Maximizer), and very expensive baking soda (which they label as sodium hydrogen carbonate instead of sodium bicarbonate so it looks like something special when it is just another name for the same exact thing you buy at the grocery!)

FWIW a salt system IS a chlorine system. It's just a way to automatically add unstabilized chlorine to your pool. If the chlorine is maintained properly the pool won't turn green. It's usually a pool on trichlor that turns green. As far as acid use, that can be minimized by proper water balance. Trichlor is extremely acidic, which is why it does not require acid BUT it does require constant monitoring of both pH and TA because it depletes TA and when that happens pH can crash dangerously low so you need to keep adding soda ash, bicarbonate, and/or borax on a regular basis instead of acid. six of one, half a dozen of the other.

We had a filter that was backwashed every 10 days or two weeks. So we were constantly adding fresh water to the pool after the backwash. We have always lived in the Houston area so we never winterized the pools. He rarely used algaecide--didn't have to. But the constant backwashing probably explains why he never had to do a major drain of the pool. I have a cartridge filter so it looks like I will either have to remove a foot or so of water from the pool every six months or so (my pool is shallow--3.5 to 4.5 feet deep) or else I should look into a SWG system. By the way, my pool builder designed the cartridge filter to go with a SWG system.

[waterbear]

I have a cartridge filter so it looks like I will either have to remove a foot or so of water from the pool every six months or so

Probably more often than that!

(my pool is shallow--3.5 to 4.5 feet deep) or else I should look into a SWG system. By the way, my pool builder designed the cartridge filter to go with a SWG system.

Cart filter would be my first choice with a SWCG and NO autofill either!

Go with salt, you won't regret it. Just stay away from natural rock construction.

[HouTex1962]

I have a cartridge filter so it looks like I will either have to remove a foot or so of water from the pool every six months or so

Probably more often than that!

(my pool is shallow--3.5 to 4.5 feet deep) or else I should look into a SWG system. By the way, my pool builder designed the cartridge filter to go with a SWG system.

Cart filter would be my first choice with a SWCG and NO autofill either!

Go with salt, you won't regret it. Just stay away from natural rock construction.

Our coping and deck is limestone so it may be a problem. Unless I develop a problem during the summer, I plan to stay with a chlorine pool and use Tri-Chlor. If it's just a matter of draining a foot or so of water every 6 months that's not a big deal to me. Thanks for your insight.

[waterbear]

I have a cartridge filter so it looks like I will either have to remove a foot or so of water from the pool every six months or so

Probably more often than that!

(my pool is shallow--3.5 to 4.5 feet deep) or else I should look into a SWG system. By the way, my pool builder designed the cartridge filter to go with a SWG system.

Cart filter would be my first choice with a SWCG and NO autofill either!

Go with salt, you won't regret it. Just stay away from natural rock construction.

Our coping and deck is limestone so it may be a problem. Unless I develop a problem during the summer, I plan to stay with a chlorine pool and use Tri-Chlor. If it's just a matter of draining a foot or so of water every 6 months that's not a big deal to me. Thanks for your insight.

Let's do the math:

for every 10 ppm FC added by trichlor you also add 6 ppm of CYA

Given a starting CYA of 30 ppm (low end of recommended range for an outdoor pool to prevent degradation from sunlight and a FC level of about 3-6 ppm (I would shoot for 4-5 ppm) , which is what would be needed to prevent any problems

AND

assuming a FC loss of 2 ppm per day (pretty much average)

THEN

Every 5 days you would be adding 6 ppm CYA along with the 10 ppm FC you have replaced (2 ppm/day)

In 50 days (less than 2 months) you would have added 60 ppm CYA bringing your CYA up to 90 ppm and now requiring you to maintain your FC between 5 to 10 ppm to maintain the same FC activity in your pool (I would shoot for about 8-9 ppm, which would now increase the speed at which you add CYA!).

OR requiring about a 50% water replacement (to drop the CYA back to about 45 ppm, close to the upper limit of where you want to be and needing you to maintain a FC level of about 5 ppm).

Even assuming a 1 ppm FC loss daily it would mean a 50% water replacement every 4 months!

Sorry, Trichlor is not the best choice in a climate with a long swim season, has a cart filter, and that does not winterize. If you do not want to go with salt but would still like the convenience of automatic chlorine dosage so you don't have to add unstabilized chlorine (sodium hypochlorite or calcium hypochlorite, which can be a problem if your calcium is high) then you can look into a peristaltic pump for dosing the liquid chlorine or one of the automatic cal hypo feeders that are available. One of these system will cost about the same or a bit less then a salt system and you will still need to buy chlorine.

[HouTex1962]

I have a cartridge filter so it looks like I will either have to remove a foot or so of water from the pool every six months or so

Probably more often than that!

(my pool is shallow--3.5 to 4.5 feet deep) or else I should look into a SWG system. By the way, my pool builder designed the cartridge filter to go with a SWG system.

Cart filter would be my first choice with a SWCG and NO autofill either!

Go with salt, you won't regret it. Just stay away from natural rock construction.

Our coping and deck is limestone so it may be a problem. Unless I develop a problem during the summer, I plan to stay with a chlorine pool and use Tri-Chlor. If it's just a matter of draining a foot or so of water every 6 months that's not a big deal to me. Thanks for your insight.

Let's do the math:

for every 10 ppm FC added by trichlor you also add 6 ppm of CYA

Given a starting CYA of 30 ppm (low end of recommended range for an outdoor pool to prevent degradation from sunlight and a FC level of about 3-6 ppm (I would shoot for 4-5 ppm) , which is what would be needed to prevent any problems

AND

assuming a FC loss of 2 ppm per day (pretty much average)

THEN

Every 5 days you would be adding 6 ppm CYA along with the 10 ppm FC you have replaced (2 ppm/day)

In 50 days (less than 2 months) you would have added 60 ppm CYA bringing your CYA up to 90 ppm and now requiring you to maintain your FC between 5 to 10 ppm to maintain the same FC activity in your pool (I would shoot for about 8-9 ppm, which would now increase the speed at which you add CYA!).

OR requiring about a 50% water replacement (to drop the CYA back to about 45 ppm, close to the upper limit of where you want to be and needing you to maintain a FC level of about 5 ppm).

Even assuming a 1 ppm FC loss daily it would mean a 50% water replacement every 4 months!

Sorry, Trichlor is not the best choice in a climate with a long swim season, has a cart filter, and that does not winterize. If you do not want to go with salt but would still like the convenience of automatic chlorine dosage so you don't have to add unstabilized chlorine (sodium hypochlorite or calcium hypochlorite, which can be a problem if your calcium is high) then you can look into a peristaltic pump for dosing the liquid chlorine or one of the automatic cal hypo feeders that are available. One of these system will cost about the same or a bit less then a salt system and you will still need to buy chlorine.

I have limestone coping and decking. Will the SWG result in corrosion of the limestone?