Are there any alternatives to lowering Ph and TA besides sodium bisulfate and muratic acid? I seem to be having a skin reaction to them.

A skin reaction is frequently an indicator of combined chloramines in your pool. Can you post test results that include those?

CC=0.5
I have been fighting this problem for some time. Have tried switching sanitizers from dichlor to Nature2 and am back to the diclor then bleach method. I have come to the conclusion with process of elimination that the product I am using to lower my alkalinity and Ph are what I am reacting to. My alkalinity is extremely high (280) on a new fill and it takes a considerable amount of muratic acid or sodium bisulfate to get it down to around 60 where my Ph seems to stabilize around 7.5.

Is there another product I can use to get the alkalinity down or is there a product I can add to the water to prevent the buildup of calcium deposits? My water is very hard (CH=360) and on a fresh fill if I don't balance the water immediatly my spa is covered in deposits overnight.

That CC of .5 is most likely your problem and not the acids. Almost any acid will lower pH but most add stuff to the water that you don't want in there.

Can you post a full set of test results?
pH
FC
CC
TA
CH
CYA

pH-7.5
FC-7
CC-.5
TA-60
CH-360
CYA-20

CYA is low due to new fill.

Thanks for the help!

Chuck,

I'm not sure how to solve your issue. I do not think we've ever had anyone post who reacted to muriatic before. You are more aware of your findings than I am but I would still suspect you may not have identified the culprit.

With your water in it's current state, do you have a reaction to it?

What happens when you add muriatic? How long does it last?

Muriatic Acid is made from burning Hydrogen and Chlorine then mixing the gas with DI (de-ionized) water. There's nothing in the acid that's not already in your pool. Just throwing that out.

Sodium Bisulfate does add sulfates to your pool which is why we encourage Muriatic acid over it for pH adjustment.

You said in one post your TA was high at 280, then posted results with your TA at 60. Maybe one was a mis type or something.

With the water in the current state I have a reaction. Lower legs, waist and only right arm for some reason. Takes a couple of weeks ofr it to completely clear up.

I said on a new fill my TA is 280. After I balance my water it is around 60.

FC 7 with CYA 20 seems excessive; half that would be plenty to keep the tub clean. I'd think you were reacting to the chlorine except you said the same thing happened with Nature2.

My tub typically has CC .5 because it's covered all the time, no UV to break it down/outgas it/whatever it is that happens to it. Is your tub usually covered? Maybe opening it up for a bit every day would help. (Just guessing here.)

There's nothing you can add to the water to reduce the CH; you'd need to soften the water before it gets into the tub in the first place.
--paulr

I'm a HS science teacher and we are covering acids/bases and mixtures vs. solutions. I am going to use parts of these posts for a discussion in my classes. I'm glad I happen to own a hot tub and was able to stumble upon this forum. Thanks for the info!

For your high school science, you might also look at this post and this post in terms of how carbon dioxide entering or leaving the water only changes the pH and does not change the TA. However, this isn't an easy concept to understand. You can also play around with this spreadsheet that will calculate all the chemical species for you and the effects of adding chemicals.

As for experiments, you should be able to make or start out with seltzer water, measure pH and TA, then aerate the water by 1) blowing bubbles into it or 2) stirring it vigorously or 3) pouring it back and forth between two glasses and then remeasure pH and TA (and can compare these three techniques to see which is most effective and why -- blowing tiny bubbles should be best due to greater surface area for air/water exchange). Then add acid or base and see its effects. The difference in behavior is due to carbon dioxide producing carbonic acid in the water and that's a weak acid so that the hydrogen part balances the bicarbonate (or carbonate) part whereas adding a strong acid or base the hydrogen (or hydroxyl) part is not balanced by the salt (sodium or chloride) part (i.e. the salt does not contribute to TA be it total alkalinity or total acidity).

I dont know if adding Borates would help he situation or not - may be worth a try?
Barry