TA lower while PH still high after using Dry Acid to Lower PH (TA was OK)

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D

Drd

Bronze Supporter
Jun 21, 2017
122
AZ
I am frustrated trying to get my chlorine level right and PH. I have high CYA of 90 which requires 7-12 FC. I just converted to liquid chlorine and installed a manual feeder which relies on my pump to distribute. I should mention I live in Arizona and a friend of mine has told me he adds about 30+ ounces a day to keep the chlorine level in our heat. The feeder is working fine but I am having to adjust my VS pump speeds to increase the RPMs so I get enough chlorine injected over night. So Chlorine is not my problem but I have had intermittent high PH issues. Just giving some background as I'm sure you will want to know all the perimeters of my pool.

So on to the PH/TA question is I added dry acid (don't want to use muriatic acid) to lower PH which I added according to the Pool calculator BUT it did not lower it to the Target PPM indicated yet it did lower my TA which I thought "dry" acid would not do. I added the dry acid directly to my pool water at the returns with the water circulating.

I read online somewhere that:
  • If the manufacture recommends you first dilute the dry acid, then definitely follow their advice. The reason is their product may react so fast in your water, that alkalinity will be reduced with no affect on your pH. So, instead of one level out of balance, you now have two.

    Is this true and why my ph is not coming down enough and TA is lowering (the instructions did say to dilute first)? Why would diluting in a bucket and then pouring into the pool be any different than pouring the dry acid and diluting right into a big bucket (pool). Not sure I get this unless there is some science behind it. Will diluting fix my problem like it says?

I just read this part which talks about the application of dry acid when it's an above ground pool or a "sports" type pool. I have a "play pool".

  • For above ground pools, dump the dry acid over the pool wall. As above ground pools are often more shallow then a typical diving pool, you may have to spread the powder in the pool to encourage the powder to dissolve. This holds true for below ground sport pools.

    Now I am really confused why I'm not able to decrease my PH according to the dosing instructions on the pool calculator but it is affecting my TA balance.
 
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Sorry, I can't answer your questions, but I know what information you are going to be asked for, so here's a head start.

What test kit are you using?
Post your full test results.
Fill in your signature with your pool info.
 
What was your starting pH, your pH goal, the size (gallons) of your pool, and the total amount of dry acid used? How are you measuring pH & TA?

Acid, regardless of dry or not, will lower both pH & TA.
 
FC 6.5, CC 0, PH 7.8 and TA 80 from PH 7.5 and TA 90. Test kit is the recommended Taylor 2006C. I have a 10,500 in ground play pool. Where do I enter a signature?

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I just don't understand why my PH rose when my TA declined after adding dry acid to lower PH values. I added a little more than a lb. Do different brands of dry acid yield different results and get weaker over time? I bought a brand from the pool store called Spa down with 95% acid per the label because that's all they carry in dry acids and the attendant told me the advantage of dry acid is it doesn't effect the TA level like muriatic acid does.
 
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Dry acid lowers pH and TA when added. The pH then climbs from aeration or the addition of high pH water. Most of the water here in the SW desert is pH >8.

You should really consider using muriatic acid. Dry acid adds sulfates to your water. As the concentration increases, it will damage plaster, concrete, metals, and is an absolute no go if you have a SWCG.

Take care.
 
The answer to your original question -

Is this true and why my ph is not coming down enough and TA is lowering (the instructions did say to dilute first)? Why would diluting in a bucket and then pouring into the pool be any different than pouring the dry acid and diluting right into a big bucket (pool). Not sure I get this unless there is some science behind it. Will diluting fix my problem like it says?
Click to expand...

is, NO that is absolutely not true. What you read online about acid using up TA faster that the pH can change is completely unscientific and is akin to an old term that was thrown around - "the Slug method". There used to be this old wives tale that, because acid was heavier than water, you could pour a big "slug" of it into the pool and it would consumer TA without changing the pH much. That idea is totally bogus and unscientific and completely gets wrong how water chemistry works (or any chemistry for that matter). Once the dry acid dissolves, it consumes the same amount of TA no matter how it is added. Now, if you dilute the acid in high TA water, some of the acid will get used up lowering the TA of the dilution water, but the volumes involved are so small that it is practically unnoticeable.

If you use dry acid it is best to broadcast it around the pool perimeter and then brush very vigorously to get it all to dissolve. Leaving any amount of dry acid sitting against plaster will damage it. This is one reason why TFP does not recommend it's use - muriatic acid is much easier to dissolve and disperse.
 
I'm just not sure how to approach the low TA verses the high PH now. If I treat the TA first I then raise the PH even higher then it is now or the reverse is lower the PH and also bring the TA down even more. Its like an endless cycle.

I disperse the dry acid over the water after the pump is running on high and circulating the water but I will be sure to brush too. I am going to say this one more time, I can not risk exposure to muriatic acid fumes for health reasons so please understand why some people choice not to work with it. If someone can tell me the exact way for me to approach my chemical imbalance I would appreciate it.
 
You do not have low TA -- just manage the pH and the TA will take care of itself. You have high TA fill water most likely, if you are using typical SW desert water. And during the summer you are adding a significant amount of water due to evaporation.

I understand about the muriatic acid. Have you investigated the use of the half strength? It has literally no fumes.
 
Thanks, I just read another post in the course of hunting for information to help me with this delema and I came across just what your saying....don't worry about the TA it's the PH I need to focus on. So why does the pool calculator instruct you to add chemicals to raise or lower based on the Taylor test ppm it seems contradictory and confusing?

I filter my fill water so I am not adding more hard water, which we have; not sure it's 100% effective at eliminating all the bad stuff, but I believe it helps.
 

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The TA issue in PoolMath and other places in Pool school is an issue we have been discussing. We feel we need to state a range, but we also know there is no real need to stress over the exact number. I force my TA down to 60 or so as that helps my pH get a bit more stable, but not perfectly as I have 130 TA water. But I also want to keep my CSI around 0 or just below, to keep calcium buildup off my SWCG.

Good you came to a resolution.

I assume you are running your fill water through a water softener? No filter will effect calcium hardness or TA.

Take care.
 
mknauss said:
The TA issue in PoolMath and other places in Pool school is an issue we have been discussing. We feel we need to state a range, but we also know there is no real need to stress over the exact number. I force my TA down to 60 or so as that helps my pH get a bit more stable, but not perfectly as I have 130 TA water. But I also want to keep my CSI around 0 or just below, to keep calcium buildup off my SWCG.

Good you came to a resolution.


Take care.
Click to expand...

Chalk this up to another member who basically figured this out his or herself, but had to go to the forum to confirm it, because it's not fully addressed in pool school.

DRD please don't get discouraged by this...The TA component is one of those things that'd be a trade off of simplicity versus providing full information in pool school for 100% of pool owners. The ranges work for 90% or better I'd say.

I went through your pain in 2015. My TA ended up being 40 the rest of that season. Nowadays it's 60, but I only adjust TA if my PH is not staying steady, and when I do adjust TA, I do it in small increments, and then make sure that my PH is still moving in one direction before I proceed at making another small adjustment to TA. Of course if PH is drifting up, there is not really a purposeful TA adjustment as you've found out. You just keep adding acid, keeping PH in range, until PH quits drifting. Then whatever TA you end up at, it is the right TA number for your pool, for that specific period of time. I've not adjusted PH or TA since April 2016. Keep up the good work!
 
mknauss said:
Signature - Click on Settings, upper right. Edit Signature.

Dry acid lowers pH and TA when added. The pH then climbs from aeration or the addition of high pH water. Most of the water here in the SW desert is pH >8.

You should really consider using muriatic acid. Dry acid adds sulfates to your water. As the concentration increases, it will damage plaster, concrete, metals, and is an absolute no go if you have a SWCG.

Take care.
Click to expand...
I am so glad you understand my dilemma, I'm new to all of this and trying hard to grasp everything to maintain my pool myself as I used to have pool service for years and discovered I was just getting ripped off bc I realize now it was never balanced or had any chlorine at times. So I pulled up my sleeves at 64 and retired and here I am folks.

I changed to Liquid Chlorine sanitation after learning a lot from the people who RO'd my pool water which was awesome and I continue to filter my pool fill water using a filter I purchased from an online pool supply co I hook-up to my hose so I can keep my water clean from the hard water (TDS) we have here in AZ. Only rain water is not filtered. I would like to get a whole house RO system one day though. I am going to put a magnetic water conditioner to put on my water line too which is more for the house fixtures/water heater etc.

One thing I think I understand better now is TA is to PH what CYA is to Chlorine both TA and CYA can make or break the PH or Chlorine which are the two primary components that need to be balanced. Which one do you address first is very controversial from everything I have read. Some people say you want to deal with TA levels first and PH levels secondary whereas others say don't concern yourself so much with the TA levels getting low pay attention to the PH levels. Some times I read up on TA and they tell you all the things that can go wrong with your pool if TA is not balanced, but I think their referring to what happens if the PH is out of wack.....logic would seem the acid in the water ultimately is the bigger concern not the alkalinity of the water.... hope I got this right!
 
Keep reading here on the forum and watching what others post and things will continue to become clearer.

I am curious what kind of hose end filter can reduce calcium in your water? Overall TDS means little, only the calcium really messes with our pool water conditions.

Good luck.
 
gregsfc said:
Chalk this up to another member who basically figured this out his or herself, but had to go to the forum to confirm it, because it's not fully addressed in pool school.

DRD please don't get discouraged by this...The TA component is one of those things that'd be a trade off of simplicity versus providing full information in pool school for 100% of pool owners. The ranges work for 90% or better I'd say.

I went through your pain in 2015. My TA ended up being 40 the rest of that season. Nowadays it's 60, but I only adjust TA if my PH is not staying steady, and when I do adjust TA, I do it in small increments, and then make sure that my PH is still moving in one direction before I proceed at making another small adjustment to TA. Of course if PH is drifting up, there is not really a purposeful TA adjustment as you've found out. You just keep adding acid, keeping PH in range, until PH quits drifting. Then whatever TA you end up at, it is the right TA number for your pool, for that specific period of time. I've not adjusted PH or TA since April 2016. Keep up the good work!
Click to expand...

:) I dig it!!!
 
When CYA is present, pH has almost no bearing on active chlorine levels. That's a common misconception in the industry that is taught as truth when in fact it is totally wrong. TA also has no direct impact on chlorine as there are no chemical interactions there. The same is true with the notion that TDS affects chlorine; it does not. What you are reading on other sites is just misinformation that gets repeated enough times that people consider it to be truth.

We have many advanced water chemistry posts here on TFP written by Richard Falk (chem geek). He has debunk most of the nonsense that parades around the pool industry as "science".

See these threads :

Pool Water Chemistry

Certified Pool Operator (CPO) training -- What is not taught
 
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I understand TDS is a generic term for solids in the water that don't dissipate and continue to accumulate over time including calcium, salt and CYA among others but these guys are bigger players in the over all scenario although I would think any solids would eventually over time reduce your filters cleaning.

I found this information on what an RO removes from water (of course the bigger the system the more it removes i'm sure):Reverse Osmosis and Removal of Minerals from Drinking Water. Reverse Osmosis will generally remove salt, manganese, iron, flouride, lead, and calcium
PreFresh Spa & Pool Water Fill Filter
 
JoyfulNoise said:
When CYA is present, pH has almost no bearing on active chlorine levels. That's a common misconception in the industry that is taught as truth when in fact it is totally wrong. TA also has no direct impact on chlorine as there are no chemical interactions there. The same is true with the notion that TDS affects chlorine; it does not. What you are reading on other sites is just misinformation that gets repeated enough times that people consider it to be truth.

We have many advanced water chemistry posts here on TFP written by Richard Falk (chem geek). He has debunk most of the nonsense that parades around the pool industry as "science".

See these threads :

Pool Water Chemistry

Certified Pool Operator (CPO) training -- What is not taught
Click to expand...

The problem is you get this stuff by piece meal. I see the correlation that CYA protects Chlorine so naturally PH would not have any effect. I hadn't heard that about TA but what I am seeing is how when things are viewed in one dimension they can also be viewed differently in another. I think everyone means well though and I appreciate the time and effort people put into imparting their knowledge to to help others. Thank you!

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mknauss said:
RO -- yes. But you stated a hose end filter. What is that?
Click to expand...

All RO's use a type medium to filter the water. I thought you saw this link if it doesn't go to the SpaDepot and look it up; PreFresh Spa & Pool Water Fill Filter

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mknauss said:
RO -- yes. But you stated a hose end filter. What is that?
Click to expand...

PreFresh Spa & Pool Water Fill Filter
 

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