pH overshot after using half dose of washing soda recommended? Measure too soon?

[ionizer]

Hi everyone,

I just got a new heater and was turning it on to test it out after install a day ago.

my Ph was like 7.3 and my TA was about 55. The heater RayPak recommends ph of at like 7.5-7.6 and TA of i think around 100, but I was shooting for 90 for the moment.

So I added some Baking Soda (13.5lbs) to get my TA up to 90 (recommended was 14lbs).

I then shortly waited a few minutes and proceeded to add Washing Soda (Arm & Hammer) to bring my pH up from 7.3 to 7.5. Recommended was basically the box of 55oz. I added about half, give or take so lets say 28oz. My filter then proceeded to run for about 30-60 minutes (it still is going now though because it is variable) at full speed.

I then went to test my pH using this new electronic pH meter I got and I got 8.2. (it had just been calibrated and validated a day ago). I figured "well this thing is useless."

So I went back to my test kit and low and behold it was over 8.0.

(1) Did I test too soon?
(2) IS a combination of adding Baking Soda (which i know adds miniscule amounts to pH) and Washing soda at close proximity the issue?

Yes, I do plan to wait about 4 more hours and test again, but the high pH really through me off and of course with a brand new heater and liner, I don't want to wait too long.

Am I being paranoid and simply need to wait a little bit or should I start considering some Muriatic acid?

I only did half the dose of washing soda recommended under the presumption I didn't want to overshoot and because I was also adding baking soda.

Thoughts?

 

[ajw22]

What test kit do you use?

What is your FC?

Did you use PoolMath to determine how much chemicals to add?

I think you are tinkering too much to achieve a level of precision that is unnecessary. PH of 7.3 and TA of 55 is nominally ok. PH of 7.2 - 8 is ok.

Low PH can corrode your heater. Low PH means below 7.0.

High PH of above 8 can cause scale long-term but is not something to panic over. Let your pool settle down. Use a good test kit. And then add MA in slow doses to get your PH down in increments.

 

[AimeeH]

You didn't need to add the washing soda to raise PH. You'll need to adjust that down with muratic acid.

Next time you need to adjust PH up and TA is in range, you can just aerate the water.....point the jets up if you can? Using a sprinkler will work too.

 

[ionizer]

What test kit do you use?

What is your FC?

Did you use PoolMath to determine how much chemicals to add?

I think you are tinkering too much to achieve a level of precision that is unnecessary. PH of 7.3 and TA of 55 is nominally ok. PH of 7.2 - 8 is ok.

Low PH can corrode your heater. Low PH means below 7.0.

High PH of above 8 can cause scale long-term but is not something to panic over. Let your pool settle down. Use a good test kit. And then add MA in slow doses to get your PH down in increments.

I use the Taylor k-2006 test kit.

Full numbers here:
FC: 3.5
CC: 0
pH: 8.0 plus
TA: 60 (prior to baking soda added)
CH: 50
CYA: 42ish
Temperature: 79F

Recent adds in past 3-4 hours:
28oz washing soda
13.5 lbs baking soda

How long after those adds should I be able to register a proper pH?

 

[AimeeH]

After about 15-30 minutes of circulating the pool water.

 

[ajw22]

I use the Taylor k-2006 test kit.

Full numbers here:
FC: 3.5
CC: 0
pH: 8.0 plus
TA: 60 (prior to baking soda added)
CH: 50
CYA: 42ish
Temperature: 79F

Recent adds in past 3-4 hours:
28oz washing soda
13.5 lbs baking soda

How long after those adds should I be able to register a proper pH?

4 hours is plenty of circulation to get a good PH reading.

Use PoolMath and assume your PH is 8.0 and target 7.6 and see how much MA it recommends. Then I might put half that amount in, let circulate for 2 hours, test again, and continue until you get PH test below 8.

 

[AimeeH]

4 hours is plenty of circulation to get a good PH reading.

Use PoolMath and assume your PH is 8.0 and target 7.6 and see how much MA it recommends. Then I might put half that amount in, let circulate for 2 hours, test again, and continue until you get PH test below 8.

Just an FYI, MA will be mixed very quickly. No need to wait hours. If brushing after addition and running pump, a test within 15- 30 minutes is generally fine.

 

[ionizer]

I was able to get my pH back down to a 7.7 roughly. I'm still not sure how I was able to overshoot so much of the pH by only using baking soda and half of the dosage of recommended washing soda. Is there some combination of temperature or other factors that would have made the pH go up so quickly?

- - - Updated - - -

Does heating your pool raise pH? I've never really had a working heater until today

 

[AimeeH]

The baking soda raised your PH a little bit....likely right to where it needed to be. Washing soda was overkill. Go to pool math and use the section at the bottom where you can calculate the effects of adding different chemicals.

Baking soda does raise PH. Just not as incrementally as much as washing soda.

 

[mknauss]

Temperature has no effect.

Baking soda does raise pH a bit. Use Effects of Adding Chemicals in PoolMath.

You can also raise pH with aeration.

 

[ionizer]

Temperature has no effect.

Baking soda does raise pH a bit. Use Effects of Adding Chemicals in PoolMath.

You can also raise pH with aeration.

So I was aware baking soda raised pH but I thought it was fractional as in some aspect of 0.0x ...I do use the pool calc app, but maybe I thought the amount was so neglible that I didn't need to even check how it changed pH because I knew I was half dosing the washing soda. Guess when I'm home I'll double check what it really did change.

 

[AimeeH]

If I were you, I'd have made the adjustment to PH first. Think of TA as the tool that helps keep your PH stable. If you get PH to the desired 7.5 and it tends to stay there after an initial adjustment, then don't mess with TA. If your PH keeps dropping THEN you'd want to adjust TA up.

 

[ionizer]

If I were you, I'd have made the adjustment to PH first. Think of TA as the tool that helps keep your PH stable. If you get PH to the desired 7.5 and it tends to stay there after an initial adjustment, then don't mess with TA. If your PH keeps dropping THEN you'd want to adjust TA up.

Didn't realize that I was worried about the alkalinity with the new heater and it only being at 50. You know what would be the good idea if someone were to make a logical decision tree flow using Microsoft Visio of all the things you should do and the simple yes-no and then go down to the next level I'd love to help make it but I'm probably not the expert to actually answer the questions on it.

 

[mknauss]

A flow chart sounds good, but I think there are too many variables.

Take care.

 

[ionizer]

A flow chart sounds good, but I think there are too many variables.

Take care.

i was thinking a flow chart of just "ordering of what to do things"

there is certainly a logical flow to how you guys approach things, i.e adjust X before Y measure. Yes, certainly the #s have too many variables, but i'm thinking one that just tells someone "next step" and once they do that, they kind of go back to the root of the decision tree and re-answer

As this is kind of like "Business Analysis workflow" and just for my forte, i would love to help put one together, but I'd need the experts to help me in guiding.

If anyone is interested in working with me on it, it wouldn't take more than an hour or two tops I am thinking. It could become part of your standard information and answer a lot of the newbie questions on what to deal with first.

Just a thought.

In any case, thanks for my info. I am back down to 7.7 w/ TA of 110 and will leave it be for now. At least Raypak won't be able to complain that my water is corrosive now

 

[AimeeH]

Hey ionizer

I like the idea but as Marty said, there are so many variables. When I said "if I were in your shoes I would have done X first" ........that's directly from my own experience over the years and understanding my TA/PH relationship. I know I have extremely low TA in my fill water. I know that's fine for me because that keeps my PH in check because I have a SWG which generally constantly cause Pah to rise-- but not with my fill water with no measurable TA or CH.

Maybe I shouldn't have even put it that way except I believe it's more important to chase PH that TA. Others with different fill water chemistry may need to pay more attention to TA with regards to calcium saturation index. I don't have to worry about that with a vinyl pool and my low CH fill water.

I think following the methods here and asking questions when they arise is a good way to learn. I've asked crazy questions in the past. But.....it helps me understand.

 

[ionizer]

Hey ionizer

I like the idea but as Marty said, there are so many variables. When I said "if I were in your shoes I would have done X first" ........that's directly from my own experience over the years and understanding my TA/PH relationship. I know I have extremely low TA in my fill water. I know that's fine for me because that keeps my PH in check because I have a SWG which generally constantly cause Pah to rise-- but not with my fill water with no measurable TA or CH.

Maybe I shouldn't have even put it that way except I believe it's more important to chase PH that TA. Others with different fill water chemistry may need to pay more attention to TA with regards to calcium saturation index. I don't have to worry about that with a vinyl pool and my low CH fill water.

I think following the methods here and asking questions when they arise is a good way to learn. I've asked crazy questions in the past. But.....it helps me understand.

I hear you. There may in fact be "many decisions trees" that need to be created. Which just means there are different approaches based on your setup.

So the very first question (there may be more before this, but one has to start somewhere) is "Do you have a liner" or "SWG vs Non-SWG"

at the moment - i'd start with my pool scenario, b/c obviously I know it best and can relate to it. We'd then expand out including other scenarios - which simply means a multi-faceted tree.

in the end, I strongly believe unless opinions are to be debated about what to do first given Situation X and Variables Y, Z, etc, that this is highly achievable. However, if opinions would warrant different answers, well then of course no decision tree can deal with that other than to present multiple options and paths.

I'm going to see if mknauss and I can work out a simple first iteration for a basic scenario. Perhaps if I can prove a decision tree is possible there, we could expand it. I also stand to reason that someone might think of situations I've not encountered that make it a "do this ..if unsuccessful, then do something else" but I've not really seen that type of direction given here. It's usually pretty adamant to repeat a direction until the end result is achieved.

There's no harm in us trying, so let's see. Obviously no one is going to give this as guidance (myself included) unless others thought it was fairly fullproof for basic situations. If it doesn't get there, then oh well, we tried

Thanks