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Help! Cloudy Water And Party In 2 Days!


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#1 teedoff

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Posted 02 July 2008 - 08:23 AM

I bought what i thought was the right thing(had ater tested and they said add 40lbs of something) was going on memory and bought soda ash instead of TA increaser. Needless to say i added 40 lbs of soda ash and now my water is completely milky looking. What can I do to neutralize this disaster before friday!...Im now in the process of backwashing and adding new water ..back and forth..this may be all thats needed or not? Any help would be appreciated. btw Im getting a high reading of chlorine..but i did shock it this morning in hopes this would help clear the water.

#2 teedoff

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Posted 02 July 2008 - 11:55 AM

someone help...anyone??..lol

#3 chem geek

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Posted 02 July 2008 - 01:00 PM

Test the pH and lower it to around 7.2 using Muriatic Acid and the water should clear up. If after lowering the pH to 7.2 you want the pH to be up to 7.5, then do not add any pH Up but instead just aerate the water. The water is cloudy because it has too high a combination of pH, Total Alkalinity (TA) and Calcium Hardness (CH). The only thing you can adjust quickly is the pH and it's probably too high due to the pH Up.

Be sure to pour the Muriatic Acid very slowly over a return flow at the deep end with the pump running and then lightly brush the side and bottom of the pool where you've added it to make sure it thoroughly mixes.

If I assume your pool is 15,000 gallons, then 40 pounds of Soda Ash would raise the pH to something like 9.9 and the TA to 400 ppm or so -- yikes! It will take 4.7 gallons of Muriatic Acid (31.45% Hydrochloric Acid) to bring the pH back down to 7.5 though the TA will still be high at 240 ppm or so. Do not add all the acid at once. Add no more than 1 gallon at a time (again, assuming a 15,000 gallon pool) and then after an hour with the pump running measure the pH, then add the next gallon, etc. You may find that you will need more acid than I described because as you lower the pH, the high TA level will force the pH back up some (from outgassing of carbon dioxide -- you've essentially made the pool way over-carbonated).

Are you absolutely sure you added 40 pounds of Soda Ash? 4 pounds sounds more like what you may have added in which case that would only take 7.6 cups of Muriatic Acid to restore the pH.

This is not an easy thing to fix, but it can be done as described. I suspect that you may have some of the pH Up in "chunks" that are undissolved in the pool. You should first remove that before anything else. Also, you may find that your filter gets clogged and that you have scaling on the walls. Remove what you can and clean the filter, but then get started on lowering the pH as soon as possible (i.e. remove physical scale or calcium carbonate chunks that are easy to remove, then add acid to clear up the water and redissolve the rest of the scale).

Richard

#4 chem geek

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Posted 02 July 2008 - 03:00 PM

Rob,

A return flow is where the pipe (called a "return" because it returns water into your pool) goes into your pool. The stream of water flowing out of the pipe into your pool when the pump is running produces very nice water circulation so pouring into that with your arm outstretched a bit away from the edge has the chemicals go into the water and flow down into the forceful water flow from the pipe. That disperses the chemical rather quickly. Doing this in the deep end if you have a floor drain works really well since there is more water to dilute the chemical in the deep end and it gets sucked down into the floor drain and across the way into the skimmer (in pools configured that way).

Some people prefer to pour chlorine into the skimmer, but I prefer to avoid exposing the equipment to the high pH and FC levels, though that is not nearly as much of a problem as with acid which should NEVER be poured into the skimmer (it simply cannot dilute enough since the acid is way, way too strong).

Richard

#5 teedoff

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Posted 03 July 2008 - 06:47 AM

Richard, thanks for the response. As I'm sure you can tell I am new at this. This is actually my mother's pool, and since I live next door I'm relegated to the maintainance duties. lol The pool was just put in last year, so I'm learning more every day. I forgot to mention the particulars of the pool, which is..its a 22,500 gal pool printed vinyl liner 8' deep end.

BTW..yes it WAS 40 pounds of soda ash..they were out of their consumer brand of soda ash so she sold me a 50 pound bag they use for commercial pools. Not sure about the cumps you are speaking about, since I cant see below about 20 inches, but I dont think there would be many clumps. I made sure I brushed the bottom thoroughly after adding any chemicals.

I went to my local pool pros shop yesterday and they pretty much told me what you just said. She recommended 2 gals of muriatic acid to start..one gal in with pump off for 2 hours, then the other gal in and pump on for 2 hours. Then she wanted to test the water agai, which I did. The first readings were very high as you suggested. The TA was 322 and the Ph was 8.8. After the acid doses and about 3 hours later the TA came down to 164 and the PH down to 7.8. She gave me another 5 pounds acid to administer and some floc vac, which I have started using this morning. The acid did nothing for the milky cloudy water, but she said the floc should clear it up. Not sure it will be clear by tomorrow though. If you have any other suggestions I would greatly appreciate it! Again this is a new pool and I'm actually trying to get my mother to understand the importance of a balanced pool. Other ppl with pools she knows tells her "oh well all I DO is add shock and chlorine and thats it". Ive researched enough myself to realize that thats NOT all there is to it. ANyway thanks again!

Tony

QUOTE(chem geek @ Jul 2 2008, 02:00 PM) <{POST_SNAPBACK}>
Test the pH and lower it to around 7.2 using Muriatic Acid and the water should clear up. If after lowering the pH to 7.2 you want the pH to be up to 7.5, then do not add any pH Up but instead just aerate the water. The water is cloudy because it has too high a combination of pH, Total Alkalinity (TA) and Calcium Hardness (CH). The only thing you can adjust quickly is the pH and it's probably too high due to the pH Up.

Be sure to pour the Muriatic Acid very slowly over a return flow at the deep end with the pump running and then lightly brush the side and bottom of the pool where you've added it to make sure it thoroughly mixes.

If I assume your pool is 15,000 gallons, then 40 pounds of Soda Ash would raise the pH to something like 9.9 and the TA to 400 ppm or so -- yikes! It will take 4.7 gallons of Muriatic Acid (31.45% Hydrochloric Acid) to bring the pH back down to 7.5 though the TA will still be high at 240 ppm or so. Do not add all the acid at once. Add no more than 1 gallon at a time (again, assuming a 15,000 gallon pool) and then after an hour with the pump running measure the pH, then add the next gallon, etc. You may find that you will need more acid than I described because as you lower the pH, the high TA level will force the pH back up some (from outgassing of carbon dioxide -- you've essentially made the pool way over-carbonated).

Are you absolutely sure you added 40 pounds of Soda Ash? 4 pounds sounds more like what you may have added in which case that would only take 7.6 cups of Muriatic Acid to restore the pH.

This is not an easy thing to fix, but it can be done as described. I suspect that you may have some of the pH Up in "chunks" that are undissolved in the pool. You should first remove that before anything else. Also, you may find that your filter gets clogged and that you have scaling on the walls. Remove what you can and clean the filter, but then get started on lowering the pH as soon as possible (i.e. remove physical scale or calcium carbonate chunks that are easy to remove, then add acid to clear up the water and redissolve the rest of the scale).

Richard



#6 chem geek

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Posted 03 July 2008 - 07:38 AM

The advice you are getting is good except for not running the pump when adding acid. She's probably thinking of the "slug" or "acid column" methods for lowering TA, but those do not work. Using a flocculant to clear the pool is a good idea as well. You'll definitely have a lot of stuff settled to the bottom in that case to vacuum up (and you do turn off the pump when using the flocculant).

As for maintaining a pool, it CAN be easy. All I add to my pool is 12.5% chlorinating liquid and nothing else except a little acid perhaps once or twice a summer season. I don't have to shock the pool, I don't use algaecides or phosphate removers, I don't need to use clarifiers or flocculants, and as I said I don't have to adjust the pH very often. I have an opaque electric pool cover that helps a lot to reduce chlorine loss in sunlight and to reduce evaporation. The pool is used 5-7 days/week and my chlorine consumption is around 1 ppm FC per day on average in a 16,000 gallon pool. It CAN be easy. Many pool users do the same thing, though many use 6% unscented bleach instead of chlorinating liquid depending on cost and availability.

It takes more chemicals and expense if you use Trichlor pucks/tabs since they are acidic and require pH Up, but they are more convenient. They increase the CYA level and that can lead to algae unless one dilutes the water to keep the CYA level lower or raises the FC level proportionately (hard to to with Trichlor without also raising the CYA) or using a weekly PolyQuat 60 algaecide or a phosphate remover.

Richard

#7 teedoff

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Posted 03 July 2008 - 08:41 AM

Richard
Thanks for the reply. What I was maning was that as far as keeping a balanced water it takes a little more than chlor tabs and shock is that not right? I think it may be worse if you refill with well water which is what we have here. After I opened the pool a few months ago I probably put a third more BACK into the pool with our well water. I know i tested the water as soon as I got it lclear after opening and thats when it was suggested I use some other balance chemicals to get the water just right. In fact I have those values still....

tds=350
CYA=40
TC=0
FC=0
PH= <6.2
TA=34
ADJ TA=22
T HARD=127

At the time I was having some green algae and thught I took care of that, but seemed to recure every few days up until a few weeks ago when I used a better algae killer instead of preventer I was using. I was thinking the recurring algae may have been due to the ph being low or maybe the TA being low as well.


now the readings are

tc=1.3
fc=1.3
ph=8.1
ta=209
adj ta=164
t hard=72


My normal weekly routine is...one chlor tab twice a week and 2...1Lb bags of shock each week...thats all I have been doing..I backwash when the pressure changes which usually shows up by the returns not showing as much water ripples in the water. Stupid way I know but one thing that discourages me is the pool guy put the pump and sand tank UNDER a deck...the deck wasnt there until after the pool installation, but he knew there would be a deck and put the pump there anyway. So I put a trap door in the deck surface to allow access to the pump lever. Also I put a shut off for the pump up on the deck railing to turn off when backwashing and such. No big deal really but I'm hoping when it comes time to replace the sand it isnt such close quarters that will make it aggravating.

ANyway it seems the flov has cleared some of the water. I can actually see about 2 feet down and see some settling on the steps so I will vacuum. I take it it well take more floc vac over the next day or so? or should I let the floc already in there work more? Thanks again for your help. I've had much trouble getting any help from the ppl who put the pool in..they seem to not know you when the bill is paid.

Tony



QUOTE(chem geek @ Jul 3 2008, 08:38 AM) <{POST_SNAPBACK}>
The advice you are getting is good except for not running the pump when adding acid. She's probably thinking of the "slug" or "acid column" methods for lowering TA, but those do not work. Using a flocculant to clear the pool is a good idea as well. You'll definitely have a lot of stuff settled to the bottom in that case to vacuum up (and you do turn off the pump when using the flocculant).

As for maintaining a pool, it CAN be easy. All I add to my pool is 12.5% chlorinating liquid and nothing else except a little acid perhaps once or twice a summer season. I don't have to shock the pool, I don't use algaecides or phosphate removers, I don't need to use clarifiers or flocculants, and as I said I don't have to adjust the pH very often. I have an opaque electric pool cover that helps a lot to reduce chlorine loss in sunlight and to reduce evaporation. The pool is used 5-7 days/week and my chlorine consumption is around 1 ppm FC per day on average in a 16,000 gallon pool. It CAN be easy. Many pool users do the same thing, though many use 6% unscented bleach instead of chlorinating liquid depending on cost and availability.

It takes more chemicals and expense if you use Trichlor pucks/tabs since they are acidic and require pH Up, but they are more convenient. They increase the CYA level and that can lead to algae unless one dilutes the water to keep the CYA level lower or raises the FC level proportionately (hard to to with Trichlor without also raising the CYA) or using a weekly PolyQuat 60 algaecide or a phosphate remover.

Richard



#8 teedoff

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Posted 03 July 2008 - 08:45 AM

btw the new values for CYA are 151 the tds is 700
forgot to mention that in the first reply



QUOTE(teedoff @ Jul 3 2008, 09:41 AM) <{POST_SNAPBACK}>
Richard
Thanks for the reply. What I was maning was that as far as keeping a balanced water it takes a little more than chlor tabs and shock is that not right? I think it may be worse if you refill with well water which is what we have here. After I opened the pool a few months ago I probably put a third more BACK into the pool with our well water. I know i tested the water as soon as I got it lclear after opening and thats when it was suggested I use some other balance chemicals to get the water just right. In fact I have those values still....

tds=350
CYA=40
TC=0
FC=0
PH= <6.2
TA=34
ADJ TA=22
T HARD=127

At the time I was having some green algae and thught I took care of that, but seemed to recure every few days up until a few weeks ago when I used a better algae killer instead of preventer I was using. I was thinking the recurring algae may have been due to the ph being low or maybe the TA being low as well.


now the readings are

tc=1.3
fc=1.3
ph=8.1
ta=209
adj ta=164
t hard=72


My normal weekly routine is...one chlor tab twice a week and 2...1Lb bags of shock each week...thats all I have been doing..I backwash when the pressure changes which usually shows up by the returns not showing as much water ripples in the water. Stupid way I know but one thing that discourages me is the pool guy put the pump and sand tank UNDER a deck...the deck wasnt there until after the pool installation, but he knew there would be a deck and put the pump there anyway. So I put a trap door in the deck surface to allow access to the pump lever. Also I put a shut off for the pump up on the deck railing to turn off when backwashing and such. No big deal really but I'm hoping when it comes time to replace the sand it isnt such close quarters that will make it aggravating.

ANyway it seems the flov has cleared some of the water. I can actually see about 2 feet down and see some settling on the steps so I will vacuum. I take it it well take more floc vac over the next day or so? or should I let the floc already in there work more? Thanks again for your help. I've had much trouble getting any help from the ppl who put the pool in..they seem to not know you when the bill is paid.

Tony



QUOTE(chem geek @ Jul 3 2008, 08:38 AM) <{POST_SNAPBACK}>
The advice you are getting is good except for not running the pump when adding acid. She's probably thinking of the "slug" or "acid column" methods for lowering TA, but those do not work. Using a flocculant to clear the pool is a good idea as well. You'll definitely have a lot of stuff settled to the bottom in that case to vacuum up (and you do turn off the pump when using the flocculant).

As for maintaining a pool, it CAN be easy. All I add to my pool is 12.5% chlorinating liquid and nothing else except a little acid perhaps once or twice a summer season. I don't have to shock the pool, I don't use algaecides or phosphate removers, I don't need to use clarifiers or flocculants, and as I said I don't have to adjust the pH very often. I have an opaque electric pool cover that helps a lot to reduce chlorine loss in sunlight and to reduce evaporation. The pool is used 5-7 days/week and my chlorine consumption is around 1 ppm FC per day on average in a 16,000 gallon pool. It CAN be easy. Many pool users do the same thing, though many use 6% unscented bleach instead of chlorinating liquid depending on cost and availability.

It takes more chemicals and expense if you use Trichlor pucks/tabs since they are acidic and require pH Up, but they are more convenient. They increase the CYA level and that can lead to algae unless one dilutes the water to keep the CYA level lower or raises the FC level proportionately (hard to to with Trichlor without also raising the CYA) or using a weekly PolyQuat 60 algaecide or a phosphate remover.

Richard




#9 chem geek

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Posted 03 July 2008 - 12:59 PM

Tony,

Your CYA is now too high. You now pretty much HAVE to use an algaecide or phosphate remover to control algae unless you dilute the water to lower the CYA level. Why did the CYA get so high? Were you shocking with Dichlor powder/granules? How did you get from a CYA of 40 to 151 so quickly? You really should not trust the pool store numbers and should get your own good test kit -- either the Taylor K-2006 kit you can get for a good online price here or the TF100 kit from tftestkits.com here with the latter kit having 36% more volume of reagents so comparably priced "per test".

You can absolutely prevent algae from growing by simply maintaining enough Free Chlorine (FC) relative to the Cyanuric Acid (CYA) level. It is the ratio of FC to CYA that determines the amount of "active" disinfecting chlorine in the water that prevents algae growth and sanitizes the water. If you never let the FC drop below 7.5% of the CYA level, you will not get algae. A decent target that is easy to remember is an FC that is 10% of the CYA level. The only exception to this is if the phosphate level gets really, really high, well over 3000 ppb. In my own pool my phosphate level is around 2000-3000 ppb yet I don't get algae growth because I follow that FC/CYA rule. This is also true for thousands of pool users at The Pool Forum and Trouble Free Pool. Yellow/mustard algae requires higher levels, but plain green algae which is the most common can easily be kept away with chlorine alone.

The problem is that there is no slow-dissolving source of chlorine that doesn't add something extra to the water. Trichlor pucks/tabs add CYA where for every 10 ppm FC that they add, they also increase CYA by 6 ppm. There are also Cal-Hypo pucks but they need special feeders and fall apart near the end and leave a residue. With Cal-Hypo, for every 10 ppm FC that they add, they also increase Calcium Hardness (CH) by 7 ppm. Finally, with Dichlor (which is always fast-dissolving powder/granules), for every 10 ppm FC that it adds, it also increases CYA by 9 ppm. So Dichlor should never ever be used for shocking unless you intentionally want to increase your CYA level.

Even at 2 ppm FC usage, with Trichlor that adds 36 ppm CYA every month so unless you have a small pool with lots of splash-out and weekly backwashing of a filter, you are likely to have the CYA get very high very quickly. Unless the FC level is raised, which you cannot do with Trichlor without further raising the CYA level, you are very likely to get algae in the pool. The only way to prevent that (i.e. to not have a high enough FC with the higher CYA level) is to use a weekly PolyQuat 60 algaecide or to use a phosphate remover.

The other problem with Trichlor pucks/tabs is that they are VERY acidic so you have to add pH Up product to keep the pH and TA from falling.

Please, please get your own good test kit if you want to take charge of your own pool. Otherwise, you will be at the mercy of your pool store -- some are good, while others are not. Generally speaking, the pool store advice, even if helpful and correct, will have you buying hundreds of dollars of chemicals that you wouldn't need if they only told you about a different approach of maintaining your pool using mostly chlorinating liquid or 6% unscented bleach as your primary source of chlorine.

Richard

#10 chem geek

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Posted 04 July 2008 - 10:32 AM

Rob,

This is up to you, but you just need to understand that if you use your chlorinator with Trichlor pucks/tabs, that the CYA level will likely increase over time. In order to prevent algae, you'll have to have a higher FC level to keep the FC/CYA ratio roughly constant and that will be hard to do using the chlorinator. Your other option is to use a supplemental algaecide (weekly PolyQuat 60) or a phosphate remover in which case you won't need to worry as much about the CYA level, at least as far as algae goes.

I would certainly never shock with stabilized chlorine. I would only shock with chlorinating liquid or bleach, though you can use Cal-Hypo if the CH isn't high (so usually for vinyl pools where CH can be lower -- in plaster pools, it's usually near saturation levels already). Where you have more of a choice is with your regular source of chlorine. For automatic dosing, you can consider The Liquidator which is talked about here positively and with some recent problems we're trying to resolve here.

Richard

#11 AndyC

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Posted 17 July 2008 - 06:51 AM

I had a similar problem. I have a well with very acidic water which I mitigate using Grade 100 Soda ash in a 50lb bag and a chemical injection pump. I have not been completely satisfied with the "dissolvability" in my chemical tank for the well, so I figured I'd give it a shot in the pool which also has very low PH. When I added it to the pool it turned brown and sank to the bottom undissolved and clogged up my DE filter. I'm going to Baking Sode in my pool and chemical tank. Just curious if there was any thoughts on my this stuff won't dissolve and turn brown in a pool.

Thanks
Andy

QUOTE(teedoff @ Jul 3 2008, 06:47 AM) <{POST_SNAPBACK}>
Richard, thanks for the response. As I'm sure you can tell I am new at this. This is actually my mother's pool, and since I live next door I'm relegated to the maintainance duties. lol The pool was just put in last year, so I'm learning more every day. I forgot to mention the particulars of the pool, which is..its a 22,500 gal pool printed vinyl liner 8' deep end.

BTW..yes it WAS 40 pounds of soda ash..they were out of their consumer brand of soda ash so she sold me a 50 pound bag they use for commercial pools. Not sure about the cumps you are speaking about, since I cant see below about 20 inches, but I dont think there would be many clumps. I made sure I brushed the bottom thoroughly after adding any chemicals.

I went to my local pool pros shop yesterday and they pretty much told me what you just said. She recommended 2 gals of muriatic acid to start..one gal in with pump off for 2 hours, then the other gal in and pump on for 2 hours. Then she wanted to test the water agai, which I did. The first readings were very high as you suggested. The TA was 322 and the Ph was 8.8. After the acid doses and about 3 hours later the TA came down to 164 and the PH down to 7.8. She gave me another 5 pounds acid to administer and some floc vac, which I have started using this morning. The acid did nothing for the milky cloudy water, but she said the floc should clear it up. Not sure it will be clear by tomorrow though. If you have any other suggestions I would greatly appreciate it! Again this is a new pool and I'm actually trying to get my mother to understand the importance of a balanced pool. Other ppl with pools she knows tells her "oh well all I DO is add shock and chlorine and thats it". Ive researched enough myself to realize that thats NOT all there is to it. ANyway thanks again!

Tony

QUOTE(chem geek @ Jul 2 2008, 02:00 PM) <{POST_SNAPBACK}>
Test the pH and lower it to around 7.2 using Muriatic Acid and the water should clear up. If after lowering the pH to 7.2 you want the pH to be up to 7.5, then do not add any pH Up but instead just aerate the water. The water is cloudy because it has too high a combination of pH, Total Alkalinity (TA) and Calcium Hardness (CH). The only thing you can adjust quickly is the pH and it's probably too high due to the pH Up.

Be sure to pour the Muriatic Acid very slowly over a return flow at the deep end with the pump running and then lightly brush the side and bottom of the pool where you've added it to make sure it thoroughly mixes.

If I assume your pool is 15,000 gallons, then 40 pounds of Soda Ash would raise the pH to something like 9.9 and the TA to 400 ppm or so -- yikes! It will take 4.7 gallons of Muriatic Acid (31.45% Hydrochloric Acid) to bring the pH back down to 7.5 though the TA will still be high at 240 ppm or so. Do not add all the acid at once. Add no more than 1 gallon at a time (again, assuming a 15,000 gallon pool) and then after an hour with the pump running measure the pH, then add the next gallon, etc. You may find that you will need more acid than I described because as you lower the pH, the high TA level will force the pH back up some (from outgassing of carbon dioxide -- you've essentially made the pool way over-carbonated).

Are you absolutely sure you added 40 pounds of Soda Ash? 4 pounds sounds more like what you may have added in which case that would only take 7.6 cups of Muriatic Acid to restore the pH.

This is not an easy thing to fix, but it can be done as described. I suspect that you may have some of the pH Up in "chunks" that are undissolved in the pool. You should first remove that before anything else. Also, you may find that your filter gets clogged and that you have scaling on the walls. Remove what you can and clean the filter, but then get started on lowering the pH as soon as possible (i.e. remove physical scale or calcium carbonate chunks that are easy to remove, then add acid to clear up the water and redissolve the rest of the scale).

Richard




#12 chem geek

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Posted 17 July 2008 - 08:25 AM

Andy,

For well water or any water high in metals, you want to avoid a high pH since that will precipitate metals causing either the water to turn color (brown is usually iron; green is often copper) or to stain or both. Soda Ash is sodium carbonate and raises both the pH and the TA. If the well water is high in either Total Alkalinity (TA) or Calcium Hardness (CH) or both, then the water is likely to be very saturated with calcium carbonate. Adding soda ash to this will cause the water to cloud and excess soda ash will form calcium carbonate crystals that just sit on the bottom and won't dissolve until the water becomes less saturated. You can use The Pool Calculator to calculate the saturation index for you water -- if it's strongly positive then increasing TA or CH or pH will cause cloudiness, scaling, or undissolved product.

Adding baking soda will increase TA with not much change in pH. Though not as dramatic as soda ash, it can still cause the same problems as noted above if the water is already saturated with calcium carbonate. You really need to get a good test kit as I described in an earlier post in this thread. For metals in the water, you need a metal sequestrant. To lower Total Alkalinity (TA), you need to follow the aeration + acid procedure described in this post. Lowering the CH is difficult if the well water used for fill is high in CH.

Generally speaking, if your pH tends to rise and not drop, then you don't need a very high TA level. If your CH is very high, you can have a much lower TA level and still have saturated water which you want for plaster pools, but the lower TA will outgas carbon dioxide more slowly making the pH rise more slowly. Lowering the TA to 70 ppm can help; I wouldn't go below 50 ppm in any event, especially if the CYA is higher then 70 ppm is as low as I'd go.

If you are using Trichlor tabs/pucks (see my cautions about rising CYA in an earlier post in this thread), then you can use 20 Mule Team Borax to raise the pH with half the rise in TA compared to soda ash. However, you normally want a higher TA when using an acidic source of chlorine such as Trichlor, but having 120 ppm TA in a pool that is high in CH can over-saturate the water making water balance difficult.

Richard

#13 AndyC

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Posted 18 July 2008 - 05:15 AM

Thanks Richard for the reply - My PH is extremely low and initial test with the strips indicate the hardness is within spec. The CH levels will not stay up, I can get them up to about 5 ppm for a day with 2 lbs of shock, but they are right back down in two days even with a auto-chlorinator (using chlorine at an alarming rate with no result). Just to be clear - the water did get cloudy but only the undissovled soda ash turned brown. I was raising the PH based on advise from Leslie's from my water analysis

Thanks
Andy
QUOTE(chem geek @ Jul 17 2008, 08:25 AM) <{POST_SNAPBACK}>
Andy,

For well water or any water high in metals, you want to avoid a high pH since that will precipitate metals causing either the water to turn color (brown is usually iron; green is often copper) or to stain or both. Soda Ash is sodium carbonate and raises both the pH and the TA. If the well water is high in either Total Alkalinity (TA) or Calcium Hardness (CH) or both, then the water is likely to be very saturated with calcium carbonate. Adding soda ash to this will cause the water to cloud and excess soda ash will form calcium carbonate crystals that just sit on the bottom and won't dissolve until the water becomes less saturated. You can use The Pool Calculator to calculate the saturation index for you water -- if it's strongly positive then increasing TA or CH or pH will cause cloudiness, scaling, or undissolved product.

Adding baking soda will increase TA with not much change in pH. Though not as dramatic as soda ash, it can still cause the same problems as noted above if the water is already saturated with calcium carbonate. You really need to get a good test kit as I described in an earlier post in this thread. For metals in the water, you need a metal sequestrant. To lower Total Alkalinity (TA), you need to follow the aeration + acid procedure described in this post. Lowering the CH is difficult if the well water used for fill is high in CH.

Generally speaking, if your pH tends to rise and not drop, then you don't need a very high TA level. If your CH is very high, you can have a much lower TA level and still have saturated water which you want for plaster pools, but the lower TA will outgas carbon dioxide more slowly making the pH rise more slowly. Lowering the TA to 70 ppm can help; I wouldn't go below 50 ppm in any event, especially if the CYA is higher then 70 ppm is as low as I'd go.

If you are using Trichlor tabs/pucks (see my cautions about rising CYA in an earlier post in this thread), then you can use 20 Mule Team Borax to raise the pH with half the rise in TA compared to soda ash. However, you normally want a higher TA when using an acidic source of chlorine such as Trichlor, but having 120 ppm TA in a pool that is high in CH can over-saturate the water making water balance difficult.

Richard






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