Muratic Acid and Biguanide

enahs · Postby **enahs** » Wed 18 Jul, 2012 19:21

I am having similar issues as others where it is hard to bring down their TA without bringing down pH too low. I am going to try the method of bringing the pH down to 7.0 (or so) which will bring down the TA but raising the pH by aeration using a fountain which will not raise TA. With that said I have also read that using MA is better than the normal sodium bisulfate that you normally find at pool stores for help with lowering TA. My question is, do I have any concern with using MA to lower TA when using Biguanide sanitizers?

Postby **chem geek** » Thu 19 Jul, 2012 23:03

No. The same procedure is used and is safe for biguanide sanitizers. You aren't lowering the pH by that much overall. Just remember to add the acid slowly over a return flow in the deep end with the pump running and then lightly brush the side and bottom of the pool where you've added the acid to ensure thorough mixing.

enahs · Postby **enahs** » Fri 20 Jul, 2012 08:15

Thanks for the response. I have a small (8k gals) above ground pool so it is all 48" deep. With that said I would assume to simply put the acid in the end of the pool furthest from the skimmer?

Also, is there any advantage or disadvantage to using MA as opposed to sodium bisulfate?

Thanks again for the response.

Postby **chem geek** » Fri 20 Jul, 2012 08:40

Yes, you can add it where you describe if there is a return outlet there. However, if you've only got a single outlet, then I suspect it might be on roughly the same side of the pool as the skimmer as in Intex pools.

Sodium bisulfate will build up sulfates over time. Using it occasionally is not a problem, but if you use it a lot then the higher sulfates can be a problem for plaster surfaces, for soft stone coping and hardscape (magnesium sulfate has very high salt recrystallization pressure) and at very high levels along with high Calcium Hardness (CH) levels it can produce calcium sulfate scale. With a smaller pool likely to be vinyl and without surrounding soft stone, these issues are unlikely to be a problem for you.

Full-strength Muriatic Acid (31.45% Hydrochloric Acid) can fume so is nasty stuff that you'll want to pour downwind. You can get half-strength (15-16% Hydrochloric Acid) that fumes a lot less and hopefully that you can get for half the price.