I live in the Central Valley, CA. I had to drain/refill almost all my water because of extremely high CYA levels. My pool water also had really high TA, but normal levels of CH for a plaster pool. TA-350, CH-240. However, my tap water has high TA and low CH. I am still working the CYA levels down, but basically, my numbers will be:

TA-250
CH-140
PH-8.0
CYA-90 and continuing to work it down to 50-60.

I am waiting to finish up the drain/refill for the CYA before adding my chlorine.

After reading other similar questions, I see that I should work on chlorine and PH first. Because I have to lower my TA and increase my CH, I was wondering the best way to tackle this. Because I am going to have to lower the PH and aerate to deal with the TA, should I tackle adding the required Calcium Chloride to raise the CH first? Can I do both at the same time or will adding acid interact with the calcium chloride for raising the CH? Thanks!

You should work on getting the TA down for a while before adding any CH. You don't want TA and CH to both be high at the same time. I suggest adding CH when TA gets down to about 150.

Thank you for the advice, I'll do that, and with a current level of CH 140, the plaster will be ok while I work on the TA? BTW, thank you for providing such a great informative site!

Yes, the plaster is fine because of the high TA level. The high TA level cancels out the low CH level, protecting the plaster. You don't want TA and CH both low, or both high, at the same time. By waiting to raise CH until the TA level is just a little high, you keep everything in balance.

As for CYA, make sure you check the shock you are using. Sodium dichlor tends to have cyanuric acid built into it, so everytime you shock your pool, you add more. Cal hypo is typically not as stabilized so it can be good to switch off to keep the cya level down. Plus, if you are adding any, remember that it tends to stay in the water, so it is usually not necessary to add again. I am only saying this because I have actually had customers add CYA to their water every week.

Thanks for the replies. No I am just using household bleach, I don't plan on adding any CYA now that I have it in a normal range. That is what was my demise before realizing that the chlorine tabs were building up CYA. Now the water is:

FC-18
CC-0.5
TA-210
CH-140
PH-7.5
CYA-65

I am working the TA down by adding muriatic acid and aerating until I get it down far enough to raise CH which will probably take a week or two, but so far, the water looks great, getting nice and clear now.

Have you been fighting algae? The chlorine level is at least twice what I would expect to see in a manually chlorinated pool. If not, suggest not adding any more bleach until FC falls to recommended levels or 7.5% of CYA... about 5 ppm FC.

Your plan in reducing TA through periodic application of muriatic acid (TA) and aeration, and the description of your pool all sounds good.

Make sure that your TA test is valid.

There is a known issue with static electricity that causes small drops on the TA test (documented all over this forum including http://www.troublefreepool.com/t-a-is-way-too-high-t11804.html)

The solution is to wipe the tip of the TA dropper bottle with a damp cloth.

Yeah my chlorine level is high because I am shocking the pool to start with. I simultaneously drained and refilled the pool, and there had been algae, so I am starting by shocking, and working the TA down. The water looks great now and I am happy to have things under control.

As far as the static effecting the results on the TA test, I did see about wiping the bottle. I have been wiping between drops when testing, but I did not know the reason. I was just following the directions in the test kit.

By now you should have an idea of what a "normal" drop looks like. Next time you do the TA test, skip the wiping step and see if the drops look normal. If you do, no worries. If they are inconsistent size or show anything else weird happening, go back to wiping.
--paulr

Ok thanks for the advice!

My latest levels are:

FC 7.0
CC 0.0
TA 130
CH 190
PH 7.0 (still working TA down)
CYA 65

I was reading about the recommended levels. My fill water has high TA, my pool gets a lot of direct sunlight here in California. With a plaster pool and these conditions, should any of the TFP target numbers be different than what's recommended for a plaster pool with bleach chlorination? Should I maintain a TA slightly higher around 100-120?

In Central Valley sun, I'd say you want CYA higher than usual, and you're already there.
Your CH is low, so if you bring down your TA more then you probably want to bring your CH up some.
Or, you could leave the TA where it is, and if you find you don't need to be adding acid constantly to fight a rising pH, then I'd say it's okay now.
--paulr