Dichlor/bleach Questions....confusion

[whodyawant]

So, bottom line, assume that HTH is Cal-Hypo and not Dichlor (or read the ingredients label, if you can) so generally do not use it in a spa unless your CH is very low and you don't mind increasing it using this product.

Okay, so I have a question here. If I was looking to convert our spa from bromine to the dichlor/chlorine method, and we have soft water would that be a way to initially raise my CYA and also increase hardness to our water, then once the CYA was high enough switch over to the dichlor/bleach method? I ask, because I already have that product on hand. Use it as my "bank" on initial refill so to speak?

Ugh, I hope you pros don't think that's a silly question.

Who

[chem geek]

So, bottom line, assume that HTH is Cal-Hypo and not Dichlor (or read the ingredients label, if you can) so generally do not use it in a spa unless your CH is very low and you don't mind increasing it using this product.

Okay, so I have a question here. If I was looking to convert our spa from bromine to the dichlor/chlorine method, and we have soft water would that be a way to initially raise my CYA and also increase hardness to our water, then once the CYA was high enough switch over to the dichlor/bleach method? I ask, because I already have that product on hand. Use it as my "bank" on initial refill so to speak?

Ugh, I hope you pros don't think that's a silly question.

Who

The Cal-Hypo increases Calcium Hardness (CH) and not Cyanuric Acid (CYA), so you could start off with Dichlor until the CYA got to around 30 ppm (you definitely want to do that first or else the chlorine will be too strong) and then use Cal-Hypo until the CH reached your target (100 ppm?), but it will take a while to raise the CH if your water is very soft (i.e. has initially very low CH). After that, you could use bleach. That is a reasonable approach.

[cocoabailey]

To lower TA you can reduce PH to 7.0-7.2 with acid and then aerate to increase PH.

The method to do this is add acid turn on jets, check, repeat as necessary until your down to around 60ppm...is this correct? Is there a post somewhere that discribes this in procedure in a little more detail (ie timings)

In a 350 gal tub 8 oz of Dry Acid will lower TA by 100ppm.

1) Calculate how much you need to lower your TA, and how much acid you need to add.

2) Add HALF (but not more than one cup or less than 1 oz) of the amount of acid you need to add.

3) Aerate for 30min, and check TA/pH.

4) If TA > goal and pH is > 7.8, goto step 2.

Example:

Your TA is 300, you want to lower it to 60ppm, in a 350 gal tub.

You need 2.4 cups dry acid.

Add one cup acid.

Aerate 30mins, check TA/pH.

TA=200 and pH=8.0

Add 6 oz.

Aerate 30mins, check TA/pH.

TA=125 and pH=8.0

Add 4 oz.

Aerate 30mins, check TA/pH.

TA=75 and pH=8.0

Add 1 oz

Aerate 30mins, check TA/pH.

TA=60 and pH=7.6

The main thing to remember is to add more acid in the beginning, and less at the end.

Hi there,

Where exactly are you getting these numbers from, I can only seem to get the pool calculator to calculate increases, but no down? Any thoughts? Thanks again for all the help!

T

[Nitro]

Hi there,

Where exactly are you getting these numbers from, I can only seem to get the pool calculator to calculate increases, but no down? Any thoughts? Thanks again for all the help!

Unfortunately The Pool Calculator doesn't have a calculation for decreasing TA. Maybe we should email the creator and ask him to add it.

8 oz of Dry Acid is just an estimate (on the low side) I calculated using the Taylor manual. Actually the figure is more like 12oz by weight (8oz by volume) to lower TA 100ppm in a 350 gal tub. That's also assuming 93% Sodium Bisulfate.

[chem geek]

Where exactly are you getting these numbers from, I can only seem to get the pool calculator to calculate increases, but no down?

In The Pool Calculator under the section "Effect of adding chemicals" you can see that in 350 gallons that 12 ounces of dry acid lowers the TA by 100 so 1.2 ounces weight lowers it by 10 ppm (unfortunately, the calculator ignores decimals for small amounts). By volume, it's 0.8 ounces or almost 5 teaspoons.

As for the effects on pH, The Pool Calculator is approximate. The accurate calculations for pH may be done in my spreadsheet, but this is not for novice users.

Richard

[Nitro]

In The Pool Calculator under the section "Effect of adding chemicals" you can see that in 350 gallons that 12 ounces of dry acid lowers the TA by 100 so 1.2 ounces weight lowers it by 10 ppm (unfortunately, the calculator ignores decimals for small amounts). By volume, it's 0.8 ounces or almost 5 teaspoons.

As for the effects on pH, The Pool Calculator is approximate. The accurate calculations for pH may be done in my spreadsheet, but this is not for novice users.

Richard

I missed that calculation about adding Dry Acid. I didn't know there were that many options. That's good to know.

[cocoabailey]

Where exactly are you getting these numbers from, I can only seem to get the pool calculator to calculate increases, but no down?

In The Pool Calculator under the section "Effect of adding chemicals" you can see that in 350 gallons that 12 ounces of dry acid lowers the TA by 100 so 1.2 ounces weight lowers it by 10 ppm (unfortunately, the calculator ignores decimals for small amounts). By volume, it's 0.8 ounces or almost 5 teaspoons.

As for the effects on pH, The Pool Calculator is approximate. The accurate calculations for pH may be done in my spreadsheet, but this is not for novice users.

Richard

Thanks Richard and Nitro,

This is starting to make a little more sense each day. OK so the tub is filled back up, and warming up. First thing I'll have to do is get my TA down n the 60-80 range(looks like 5-7tsp ofdry acid should do the trick), and ensure PH is good, then I can start the build up of CYA by adding 2.2 tsp (400gal tub) of dichlor a day for 7 days. After that I can go to bleach, which would be 2-3oz per use(before or after soaking), (looking to keep FC between 4-5) shock once a week to 12ppm (can you use dichlor to shock or will this build up the CYA too much over time?)

Once TA and PH are stable Borates can be added in. Can this be done before the CYA reserve is built up? (during the initial 2.2tsp a day or must you wait?) Since the pool calculator is referring to baking soda, should I just follow the instructions on the jug (150g/1000L)? Or do one of you possibly have another suggestion?

Again thanks to you both for your insight, without I would be lost in the wood.

T

[Nitro]

This is starting to make a little more sense each day. OK so the tub is filled back up, and warming up. First thing I'll have to do is get my TA down n the 60-80 range(looks like 5-7tsp ofdry acid should do the trick), and ensure PH is good, then I can start the build up of CYA by adding 2.2 tsp (400gal tub) of dichlor a day for 7 days. After that I can go to bleach, which would be 2-3oz per use(before or after soaking), (looking to keep FC between 4-5) shock once a week to 12ppm (can you use dichlor to shock or will this build up the CYA too much over time?)

You can shock with Dichlor, until your CYA is 20-30ppm. Once that happens, switch to bleach, and don't use Dichlor until your next refill.

I suggest measuring your Baseline Chlorine Demand (CD) before you start using the tub. It's handy to know. Just shock to 10ppm FC with Dichlor, wait 24 hours and measure FC again. CD = 1 - [2nd FC] / [1st FC]. THIS post explains it in detail.

Once TA and PH are stable Borates can be added in. Can this be done before the CYA reserve is built up? (during the initial 2.2tsp a day or must you wait?) Since the pool calculator is referring to baking soda, should I just follow the instructions on the jug (150g/1000L)? Or do one of you possibly have another suggestion?

You can add Borates anytime after your water is balanced.

I'm not familar with your brand of Borates. Is it pH balanced? I would just follow the instructions.

[cocoabailey]

This is starting to make a little more sense each day. OK so the tub is filled back up, and warming up. First thing I'll have to do is get my TA down n the 60-80 range(looks like 5-7tsp ofdry acid should do the trick), and ensure PH is good, then I can start the build up of CYA by adding 2.2 tsp (400gal tub) of dichlor a day for 7 days. After that I can go to bleach, which would be 2-3oz per use(before or after soaking), (looking to keep FC between 4-5) shock once a week to 12ppm (can you use dichlor to shock or will this build up the CYA too much over time?)

You can shock with Dichlor, until your CYA is 20-30ppm. Once that happens, switch to bleach, and don't use Dichlor until your next refill.

I suggest measuring your Baseline Chlorine Demand (CD) before you start using the tub. It's handy to know. Just shock to 10ppm FC with Dichlor, wait 24 hours and measure FC again. CD = 1 - [2nd FC] / [1st FC]. THIS post explains it in detail.

Once TA and PH are stable Borates can be added in. Can this be done before the CYA reserve is built up? (during the initial 2.2tsp a day or must you wait?) Since the pool calculator is referring to baking soda, should I just follow the instructions on the jug (150g/1000L)? Or do one of you possibly have another suggestion?

You can add Borates anytime after your water is balanced.

I'm not familar with your brand of Borates. Is it pH balanced? I would just follow the instructions.

Great Formula Nitro, I am definetely going to do that. One question in regards to that though, you only do this test once you start using chlorine....right? I am suspecting it is as you are referring to chlorine.

I have lowered my TA to the desired range, but now the PH is low (in the area 0f 6.5), if I add soda ash, PH+, or borax won't that just bring my TA back up to where it was in the beggining?

My appologies for so many questions, I am just trying to get this right the first time. As always, your insight is truly aprreciated! Thanks again.

T

[Nitro]

Great Formula Nitro, I am definetely going to do that. One question in regards to that though, you only do this test once you start using chlorine....right? I am suspecting it is as you are referring to chlorine.

You calculate Baseline CD right after you refill your tub, and shock with Dichlor the first time. I assume you are going to be using Chlorine (i.e. Dichlor/Bleach), and not Bromine.

I have lowered my TA to the desired range, but now the PH is low (in the area 0f 6.5), if I add soda ash, PH+, or borax won't that just bring my TA back up to where it was in the beggining?

Your pH is too low. You tried to lower TA too quickly. When you follow that procedure, make sure you wait long enough for the pH to get up to 8.0 before you add Acid. It may take longer than 30min, depending on your tub (i.e. number of jets etc.). If your TA was 75 and your pH was 8.0 (the last step), adding 1 oz Acid, should have dropped TA to ~65, and pH to ~7.0. Aeration would have then raised pH to the mid 7's.

You need to Aerate (anytime you need to raise pH start aerating). You can add Borax which will raise pH more, and TA a little. What is you TA at BTW?

[cocoabailey]

Great Formula Nitro, I am definetely going to do that. One question in regards to that though, you only do this test once you start using chlorine....right? I am suspecting it is as you are referring to chlorine.

You calculate Baseline CD right after you refill your tub, and shock with Dichlor the first time. I assume you are going to be using Chlorine (i.e. Dichlor/Bleach), and not Bromine.

I have lowered my TA to the desired range, but now the PH is low (in the area 0f 6.5), if I add soda ash, PH+, or borax won't that just bring my TA back up to where it was in the beggining?

Your pH is too low. You tried to lower TA too quickly. When you follow that procedure, make sure you wait long enough for the pH to get up to 8.0 before you add Acid. It may take longer than 30min, depending on your tub (i.e. number of jets etc.). If your TA was 75 and your pH was 8.0 (the last step), adding 1 oz Acid, should have dropped TA to ~65, and pH to ~7.0. Aeration would have then raised pH to the mid 7's.

You need to Aerate (anytime you need to raise pH start aerating). You can add Borax which will raise pH more, and TA a little. What is you TA at BTW?

Hey Nitro,

So when you say shock the tub the first time, that is bringing the FC up to 12 ppm. I thought we just add two tsp a day to build up the CYA. Then start shocking when switching over to chlorine. So you're saying I should shock to 12 now?

With the TA lowering procedure, I should aerate before adding acid, I honestly thought it was the oppsite, add the acid and then aerate to build PH back up. That might explain why my water has a greenish/brown tinge to it. Any suggestions on what I should add to clear it up? Acid, or Baking Soda?

The whole aeration thing doesn't seem to be working that great for me, and I have a lot of jets.

Need more time I am guessing.

My TA is somewhere in the 50-80 range (I am guessing 60). I can't give you an exact number because I don't have my good test kit yet, still trying to sort this out with strips for now. I'll take a water sample to the spa shop later in the week once I think the CYA is where it should be so I can confirm things prior to switching over to bleach.

Your right before, I meant chlorine, not bromine. Any ideas on the brownish green water? It is very clear, just has a slight tinge to it.

Thanks again for all your assistance.

T

[Nitro]

So when you say shock the tub the first time, that is bringing the FC up to 12 ppm. I thought we just add two tsp a day to build up the CYA. Then start shocking when switching over to chlorine. So you're saying I should shock to 12 now?

It's ok to shock with Dichlor after you refill. I usually do, just to clear out any nasties left over in the pipes. However, don't shock until you get your water balanced. See below.

With the TA lowering procedure, I should aerate before adding acid, I honestly thought it was the oppsite, add the acid and then aerate to build PH back up. That might explain why my water has a greenish/brown tinge to it. Any suggestions on what I should add to clear it up? Acid, or Baking Soda?

You should aerate before, during and after. (i.e. the whole time) You should also aerate any time your pH is < 7.4 (i.e. if you add anything acidic MPS, Acid etc.).

That greenish/brown tinge are metals in your water, probably showing because of your low pH.

The whole aeration thing doesn't seem to be working that great for me, and I have a lot of jets.

Need more time I am guessing.

My TA is somewhere in the 50-80 range (I am guessing 60). I can't give you an exact number because I don't have my good test kit yet, still trying to sort this out with strips for now. I'll take a water sample to the spa shop later in the week once I think the CYA is where it should be so I can confirm things prior to switching over to bleach.

My mistake. I thought you had a good test kit. You really need one BEFORE doing that TA lowering procedure. A TA range of 50-80 is too large. You need to know within 10ppm. If pH isn't rising from aeration, my guess is it's closer to 50ppm.

Your right before, I meant chlorine, not bromine. Any ideas on the brownish green water? It is very clear, just has a slight tinge to it.

You don't want to leave your pH that low for too long.

I suggest you add Baking Soda to raise you TA right now. Add 1 Tablespoon Baking Soda, wait 30 min then measure your pH and post it here. Keep aerating the whole time.

[cocoabailey]

So when you say shock the tub the first time, that is bringing the FC up to 12 ppm. I thought we just add two tsp a day to build up the CYA. Then start shocking when switching over to chlorine. So you're saying I should shock to 12 now?

It's ok to shock with Dichlor after you refill. I usually do, just to clear out any nasties left over in the pipes. However, don't shock until you get your water balanced. See below.

With the TA lowering procedure, I should aerate before adding acid, I honestly thought it was the oppsite, add the acid and then aerate to build PH back up. That might explain why my water has a greenish/brown tinge to it. Any suggestions on what I should add to clear it up? Acid, or Baking Soda?

You should aerate before, during and after. (i.e. the whole time) You should also aerate any time your pH is < 7.4 (i.e. if you add anything acidic MPS, Acid etc.).

That greenish/brown tinge are metals in your water, probably showing because of your low pH.

The whole aeration thing doesn't seem to be working that great for me, and I have a lot of jets.

Need more time I am guessing.

My TA is somewhere in the 50-80 range (I am guessing 60). I can't give you an exact number because I don't have my good test kit yet, still trying to sort this out with strips for now. I'll take a water sample to the spa shop later in the week once I think the CYA is where it should be so I can confirm things prior to switching over to bleach.

My mistake. I thought you had a good test kit. You really need one BEFORE doing that TA lowering procedure. A TA range of 50-80 is too large. You need to know within 10ppm. If pH isn't rising from aeration, my guess is it's closer to 50ppm.

Your right before, I meant chlorine, not bromine. Any ideas on the brownish green water? It is very clear, just has a slight tinge to it.

You don't want to leave your pH that low for too long.

I suggest you add Baking Soda to raise you TA right now. Add 1 Tablespoon Baking Soda, wait 30 min then measure your pH and post it here. Keep aerating the whole time.

OK done waiting, unfortunately is I shocked when I was waiting for a reply.....is this going to be a big problem? I'll post my TA as soon as 15 min is up.

T

[Nitro]

Not a problem. We just need to get your pH up around 7.5. Check both your pH and TA and post them here. I'm more interested in pH though.

[cocoabailey]

Not a problem. We just need to get your pH up around 7.5. Check both your pH and TA and post them here. I'm more interested in pH though.

PH6.9

TA 50

[cocoabailey]

So in theory I should add approximately 7 tsp of baking soda....right?

[Nitro]

So in theory I should add approximately 7 tsp of baking soda....right?

No, add ONE Tablespoon of Baking Soda for now. We don't want to overshoot it. How many gal is your tub again?

Keep aerating for another 20 min, then check TA/pH. Post them here.

[cocoabailey]

400 gals

[Nitro]

Ok, I was assuming 350. Not a problem. I'd say after the 20 mins of aeration, check your TA/pH again and post them here. You may need to add one more Tablespoon of Baking Soda.

As long as we get your pH in the mid to upper 7's you're safe. If you let the pH sit below 7.0 for a long time that could start causing corrosion. We don't want that.

[cocoabailey]

So in theory I should add approximately 7 tsp of baking soda....right?

No, add ONE Tablespoon of Baking Soda for now. We don't want to overshoot it. How many gal is your tub again?

Keep aerating for another 20 min, then check TA/pH. Post them here.

Looks like I am at around 7 for ph and 45-50 for TA, tub is 400 gal, water is still brown/green tinge? Nobody said learning something new is always easy.

Thanks again for the help!

T

[Nitro]

Do you know your Calcium Hardness level?

Also, exactly how much Dichlor have you added to your tub so far?

[Nitro]

Looks like I am at around 7 for ph and 45-50 for TA, tub is 400 gal, water is still brown/green tinge? Nobody said learning something new is always easy.

This is difficult, because the TA test is not accurate. The good news is, this only needs to be done after you refill.

Let's go with TWO tablespoons Baking Soda this time.

Aerate another 20 min, and post TA/pH.

[cocoabailey]

Looks like I am at around 7 for ph and 45-50 for TA, tub is 400 gal, water is still brown/green tinge? Nobody said learning something new is always easy.

This is difficult, because the TA test is not accurate. The good news is, this only needs to be done after you refill.

Let's go with TWO tablespoons Baking Soda this time.

Aerate another 20 min, and post TA/pH.

To be totally accurate, I just looked up my spa capacity in my book and it is actually 390 gal, sorry about that one.

7PH

50 TA

So far I have added a total of 7 tsp of dichlor, 2 initially which dissapated in a few hours after adding it in, then after some more reading and probably confusion on my part I add 5 more tsp to shock, but that is it so far.

T

[Nitro]

7PH

50 TA

Is this after you added the 2 TBS Baking Soda I told you to add? If not, add it now, aerate for 15 mins and check TA/pH. If so, add another 2 TBS Baking Soda, aerate 15min and check again.

I don't know why you're TA is not rising. You should be up to 60ppm by now. Now you know why you need a good drop test kit.

So far I have added a total of 7 tsp of dichlor, 2 initially which dissapated in a few hours after adding it in, then after some more reading and probably confusion on my part I add 5 more tsp to shock, but that is it so far.

Keep track of how much Dichlor you add. After you add a TOTAL of 15 tsp of Dichlor you can switch to bleach.

[cocoabailey]

7PH

50 TA

Is this after you added the 2 TBS Baking Soda I told you to add? If not, add it now, aerate for 15 mins and check TA/pH. If so, add another 2 TBS Baking Soda, aerate 15min and check again.

I don't know why you're TA is not rising. You should be up by 60ppm by now. Now you know why you need a good drop test kit.

So far I have added a total of 7 tsp of dichlor, 2 initially which dissapated in a few hours after adding it in, then after some more reading and probably confusion on my part I add 5 more tsp to shock, but that is it so far.

Keep track of how much Dichlor you add. After you add a TOTAL of 15 tsp of Dichlor you can switch to bleach.

I agree Nitro, I definitelly need a good test kit, and I do plan on getting one. From what I have read here on this forum they seem hard to get here in Canada. I am going South in a week so I was going to try and pick one up when I am down there. From the post I read it seemed I could just get away with adding the dichlor for the predetermined amount of time, then switch to bleach once I had a complete water test done to confirm everything was where it should be....you got to love it when a plan comes togeather At least I am learning all kinds of new information and I do enjoy that!

So the 15 tsp of dichlor includes shocks and all? Should I still be trying to maintain a constant FC of 4-5 ppm during this time?

I have added another 2Tbs, will post how it works out in 20.

Thanks again for the help Nitro, it is appreciated!