What TA range is correct? TF-100 instr. or Pool School?

[AaronGo]

Simple question - the instructions in my TF-100 test kit say 100-120 is the desired TA range for a non-SWG pool, but the Pool School says 70-90 is the desired range (plaster pool w/ bleach). I'll assume the Pool School range is correct, but can someone please confirm? Thanks!

 

[Richard320]

Both. It's just a difference of opinion.

And it doesn't really matter much unless you have some sort of extreme problems, which I won't get into here for fear of derailing the thread over something that affects on a small fraction of a percentage of pools.

Get CYA into range. Maintain proper FC for that level of CYA, and keep pH in the comfort zone (7.2-7.8) and you won't need to worry about TA. It will settle down and find its own happy level eventually.

 

[Vette]

TA is one of the least mission-critical level there is. As Richard pointed out, PH is the important one.

 

[AaronGo]

Thanks, good info. So I looked at the pool school some more and found

The ideal TA level depends on several factors. If you are using acidic chlorine sources, such as trichlor or dichlor, keep TA on the high side, perhaps between 100 and 120. If you have a SWG, or if you commonly run water features such as a spa, waterfall, or fountain, keep TA on the low side, between 60 and 80. Otherwise levels between 70 and 90 are good. Pools with plaster surfaces should factor their CSI into the preferred TA level decision. Pools with vinyl liners can tolerate high TA levels reasonably well.

My TA is currently at 60 (per test done yday) and my goal is to get it to 80, fyi. I do have a spa spillover, so will look to keep it at 60-80 per the above.

 

[linen]

How is your ph stability? If your ph is stable, don't mess with TA (unless it starts to get down to 50 ppm).

 

[AaronGo]

Define "stability" I have to add some acid every so often, but not like I was before. In the early stages I was adding acid every day, but now I am adding 16 oz of acid every 3-5 days. We have a spa spillover so it gets 10 hours of aeration a day, which will raise pH some.

I am little OCD about the chem levels, so want to get everything, including the TA, where they should be.

 

[linen]

I am little OCD about the chem levels, so want to get everything, including the TA, where they should be.

Be OCD on not letting your FC drop below minimum normal level, but don't be OCD on TA. There really is no "where they should be" for TA, each pool really is different. The 70-90+ is really a guideline.

With that said, since you are getting so much aeration, your TA likely will continue to go down since you have to lower ph often. The problem with having TA low is that your ph can swing around fast. If you are not having problems with that, I would not raise your TA yet...but I would not let it go below 50 ppm.

 

[AaronGo]

thanks. I already added baking soda on Sunday to get the TA up some, but going forward I will monitor it weekly and work on keeping it above 50.

 

[anonapersona]

AaronGo, you may want to determine the TA of your tap water. We have had so much rain recently that instead of adding fill water we are filled by rainwater which has low TA. As the rains taper off in the summer as they normally do, your TA will be more controlled by tap water. My tap water has TA of 340, depending on exactly where your water comes from (lake or well) yours may be quite different. So, don't force the TA up too much.

As linen said, 50 is low, I keep 60 as a minimum here but only once in 4 years have I had to add baking soda and that was in anticipation of using trichlor tablets for a vacation. The TA of 60 I had finally gotten to, where pH was rather stable, is too low for the acidity added by trichlor tablets.