Muriatic Acid - Calling all Chemistry Majors!

Jimbolo

LifeTime Supporter
Feb 3, 2010
56
Hello All, So I've got some light mineral build up on the block that rims the upper edge of my pool above the water line. And I've also got some mysterious very heavy spots (the build up and the spots look to be the same thing). The spots are mysterious because they are in random places above the water line, they're not near any jets or returns, not in any corners or crevices etc., and they appear to bleed downward from the main area that is about 2-3 inches across. Almost like the minerals are is oozing from spots on the block.

My father in law said "hit it with some of that muriatic acid". So I put some in a spray bottle (had gloves on and was VERY careful with it) and hit the heavy spots. The acid seemed to fizz a lot when sprayed on the mineral spots, but not so much when sprayed on places with less buildup.

So here are my questions: Could I potentially be hurting anything besides screwing up my Ph a little bit? Is muriatic acid a good thing to be using on these spots or is there something better? What makes it fizz like that?

Thanks for all the help.

Jim.
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,475
SW Indiana
Treating with muriatic is the normal procedure.

The fizzing is the reaction of the acid with the mineral, which is probably a calcium compound.

You may want to check into your water chemistry to see if you have excess hardness in the pool water.
 

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
23,036
SouthWest Alabama
Can you post a pic of the buildup and a full set of test results.

It sounds like calcium scaling and that would explain the fizzing but a photo and test results will help us more.
 

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
23,036
SouthWest Alabama
Actually your numbers wouldn't have been useless but you told us what we needed to know. That your CH is high. Muriatic acid is the drug of choice on calcium scaling. Just be careful using it and keep an eye on your pH.
 

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