My TA (Total Alkalinity) won't go down.

[FlyboyTR]

The water fill on our new pool was complete on 8/2/09. The fresh water looked like this:
FC 1.8
CC 0.0
TA 120
PH 8.0
CH 10
CYA 10
I added 64oz of CYA (all I had at the time), and 24 oz of muriatic acid to try to drop the PH to 7.5. Also added salt to get the level up to 3300 PPM.

On 08/03/09:
FC 1.0
CC 0.0
TA 110
PH 7.4
I added ½ of the recommended CH in small doses throughout the day.

On 8/4/09 (I also took a water sample to the PD and his numbers matched mine exactly):
FC 1.0
CC 0.0
TA 110
PH 7.5
CH 40
CYA 25
I added another 64oz of CYA (got about 1.5 lbs to go), the last half of the CH and 56oz of muriatic acid to drop the TA to 70 (based upon a PH drop to 7.0). I built a “sprinkler” on one of the return jets to spray the return water into the air…to raise the PH.

This evening, 08/05/09, I think the numbers look pretty good with the exception of the TA. It is still at 100. It only dropped 10 points after the addition of 56oz of MA.
FC 2.5
CC 0.0
TA 100
PH 7.5
I did not do a CYA test as I will be adding the last part of the CYA this evening. I NEED some guidance on what to do to get the TA to drop. I followed the recommendations on the Pool Computer for the amount of MA…but the TA drop is negligible. What do I do now? …Keep adding MA till something happens? :?:



Travis :?

 

[FlyboyTR]

Sorry...I forget to include that the reason for wanting my TA at 70 is to accomodate the addition of borates. I have been so amazed at the difference in the water quality in our hot tub since changing to BBB and the addition of borates.

Travis

 

[H2O_Keeper]

A couple of things....

You should wait at least another 2-3 days for the CYA to fully dissolve in your pool. I have seen it take about to 4 days before and the rule of thumb on the forum is one week.

Regarding the TA, I have a 16x32 pool as well and my depths etc it works out to be 21000 gallons. If I was to put in the same 84 ounces of MA (I am assuming 32% strength) my TA would only drop 16. I dont think you are off that far.

Try http://www.poolcalculator.com and see the effects of adding chemicals on the bottom.

 

[FlyboyTR]

I was basing the MA on the quantity listed to drop the PH to 7.0. I had not played with the "effecty of adding chemicals" tool on the bottom of the Pool Calculator. Thanks for that tidbit! According to that I need to add 115 oz of MA to drop the TA by 30 points. ...so...is that what I need to do?

Travis

 

[Butterfly]

What strength muriatic acid are you using?

 

[FlyboyTR]

31.5%

 

[reebok]

According to that I need to add 115 oz of MA to drop the TA by 30 points. ...so...is that what I need to do?

not if it drops your ph way too low which I'm sure it will. everything you need to know is in this article. it will work, sooner or later
pool-school/lowering%20total%20alkalinity

 

[Butterfly]

not if it drops your ph way low which I'm sure it will. everything you need to know is in this article. it will work, sooner or later
pool-school/lowering%20total%20alkalinity

Yep, what reebok said.

 

[FlyboyTR]

Thanks for the link! After reading it...I realized that I had read it back in the beginning of this journey. ...just forgot! ...so, I need to just keep dropping my PH to 7.0, aerate to raise the PH...and keep adding MA until things get magical. I believe I will check the PH several times a day and keep adding MA to maintain around a 7.0 PH. If I understand correctly...that should help to speed things along. THANKS!!!!!!

 

[reebok]

good luck. I think you will find that it will take days to get your ph up even a little bit. it's not like shocking where you can add every hour because algae is consuming your chlorine. I had two heavy duty pvc aerators (like this one my-aerator-t7799.html) and it took mine days to get to 7.2 from 7.0. it was not a quick process at all. I wasn't running the pump 24 hours though (more like 8) so that can make a big difference.

 

[dmanb2b]

I agree w reebok...I successfully lowered my TA from 300+, used the same type of homebuilt pvc aerator ran the pump 24hrs a day for 5 days and added a total of 6-7 gallons of MA, net result TA is now between 70-80. Running non-stop I was able to add about 1 gal of MA roughly every 16 hrs of pump run time...ie about a quart every 3-4 hrs. I also found that keeping the PH on the low side help speed up the process....I would drop it to 7, let it rise to just above 7.2 and drop it again.

Granted water volume will also play into the time required...I only had to aerate a 13.5k gal pool

good luck

 

[Guest]

According to that I need to add 115 oz of MA to drop the TA by 30 points. ...so...is that what I need to do?

not if it drops your ph way too low which I'm sure it will. everything you need to know is in this article. it will work, sooner or later
pool-school/lowering%20total%20alkalinity

Here is a more complete article on lowering TA:
how-to-lower-ta-t5341.html

 

[FlyboyTR]

Thanks for the additiona link! ...sincerely appreciate everyone's help! Question... why is the bottom limit 7.0 for this process when dealing with a vinyl liner?

 

[frustratedpoolmom]

Low PH can be very damaging to the vinyl, making it brittle/easily damaged.

 

[FlyboyTR]

Thanks Frustratedpoolmom! I will keep the PH 7 or above while attempting to lower the TA. :-D

Travis

 

[fordman]

But how long would it have to be below 7 for it to do damage you would notice?

 

[JasonLion]

A vinyl liner can absorb quite a bit of chemical damage before you will notice anything. Low PH can take many years off the life of the liner without anything obvious happening. You often don't notice anything till later when it fails young.

The rate of damage is a combination of just how low the PH gets and how long it is low. Really low for a short time is about the same as slightly low for a long time. Things get really bad when the PH is really low for a long time.

 

[fordman]

Well ok mine was down to 6.8 for maybe a couple hours if that went a little to far while I was running my arerator.

 

[JasonLion]

6.8 for several hours won't do anything significant. 6.0 for several weeks, or 4.0 for a few days, will.

In general, you always want to be methodical, test carefully, measure carefully, keep the levels in range. If you start allowing small errors, they might grow into larger errors later. But making a small error now and then is not a big deal, and you shouldn't worry about it.

 

[FlyboyTR]

Upon the advice of the great folks on this forum…I continued through several more rounds of attempting to lower my TA by adding MA to drop my pH to 7.0 (thereby lowering my TA) and then aerating to raise the pH. The writer that said "it may not happen quickly" was correct! After three more rounds with virtually no change in TA, things started to move! Thank you for holding my hand. :handshake: As of last evening and 8 application of MA my TA was 70 and the pH 7.2! Still aerating to raise the pH.

If the weather holds (it’s pouring rain right now) and the numbers are good we will be adding our Borax & MA today.

After testing the water yesterday and recording my numbers…using my trusty TF-100 Test Kit, I took a sample by the little PD that has been so helpful and supportive of our “self-install” project. His water test numbers have almost matched the TF-100 test results exactly! However, yesterday the owner was not there and his part time person tested the water for us. Suddenly :grrrr: we needed an endless amount of products to correct this problem…that problem…and the potential for…?????? Needless to say all I purchased was 4 gallons of muriatic acid. …which left him more confused than the test numbers he provided for me.

Anyway, this is what our numbers looked like and I will include the PD’s numbers. This is truly another testament to having a good test kit and not depending on someone else to control your pool destiny.

TF-100 ..........Pool Dealer

FC 7.0................2.7
CC 0.0................3.5
TC 7.0................6.2
pH 7.2................7.7
CH (no test)........120
TA 70.................28
CYA 75................40
Salt 3600 .............4300 (I used the new test strips I ordered from David @ TF)

With the exception of still needing to raise the pH does it look like I'm ready for the addition of Borax?

I have also turned my SWG from 60% down to 45% in an attempt to get my FC between 3 & 5. Thanks again for all the help and guidance!

Travis