Using muriatic acid in vinyl pool? Yes or no?

Coilshot

New member
Apr 13, 2020
3
Florida
I have an 18' round AG pool. I installed a new SWG and pump. Yes I know what I got is over kill for the pool size. But we'll be getting a bigger pool later. The info on the new SWG Blue works BLSC20-T says not to use dry acid to reduce PH. Pool store says not to use MA because it will damage the vinyl...? Then how do I lower my PH if I cant use either?
Test samples were 12 hours apart.
Pool store test: Morning
FC – 3
CC –0
PH–7.8
TA –120
CH – 150
CYA –50

My Test: eveing
FC – 2.5
CC –0
PH–8
TA –110
CH – 150
CYA –50
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
29,843
Laughlin, NV
Welcome to the forum!
Use muriatic acid. No issue. Pour it in slowly at the return flow from the pump. Brush the area to mix it in well, if necessary.
Looks like you need to raise your CYA a bit and keep a higher FC. Otherwise looks good.
I suggest you read ABC's of Pool Water Chemistry.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,645
San Dimas, CA (LA County)
Pool stores prefer to sell dry acid. It comes in nice plastic canisters and stacks neatly on the shelves, like all the other chemicals. Muriatic Acid has to be handled carefully so it doesn't spill and doesn't vent all over something. That's why they push dry acid.
 

Coilshot

New member
Apr 13, 2020
3
Florida
Yup, planning on adding 1 pound CYA. And increasing SWG %. Thanks for the info, was pretty sure it was something like that. I'll be adding MA to my shopping list.
 

IceShadow

Gold Supporter
TFP Guide
Jun 8, 2019
2,177
Milwaukee, WI
Pool stores prefer to sell dry acid. It comes in nice plastic canisters and stacks neatly on the shelves, like all the other chemicals. Muriatic Acid has to be handled carefully so it doesn't spill and doesn't vent all over something. That's why they push dry acid.
Plus you can buy MA at any hardware store.