how much acid

I have about 27,000 gallons and my ph is off the chart,i have some acid from a motorcycle battery i never used any ideas on how much to start with? Thank you

Do NOT use the battery acid!
Do NOT use the battery acid!
Do NOT use the battery acid!
Do NOT use the battery acid!
Do NOT use the battery acid!

Oh, yeah, do NOT use the battery acid! If it's ever been in a battery, it will poison you, in your pool. If it hasn't, it may, or may not, be pure sulfuric acid. You could use pure sulfuric acid to LOWER the pH in your pool, but you don't know that battery acid doesn't have 'additives' in it for batteries, but not for pools!


Back to the original problem you mention: is your pH off the chart LOW or off the chart HIGH? If it's HIGH (over 7.8) you need acid. If it's LOW (below 7.0), you borax or washing soda.

The acid is pure sulfuric acid brand new never opened. And my ph is high.Thanks

As long as it's pure sulfuric, it's OK. Not as good as hydrochloric, at least for concrete pools, but one dose won't cause problems even there. Use small doses, however. I have no idea what the strength is, compared to standard muriatic.

Got back from walmart a few hours ago picked up the hth 6 way test kit(it was the best one they had) and the last 7lb bottle of hth ph minus. My chlorine and ph are high(off the scale) the TA was around 150 and it only turned the blue to a pale red on the test kit so maybe a little higher. On the total hardness test the water didn't turn red but did go to blue after 10 drops so i guess 100ppm and the CYA was 90ppm. Just did a vacum to waste and a long backwash to dump some water(couple hundred gallons), should i add the ph minus or keep dumping water? Thanks for your time and help

I guess I'm going to throw the question back to you: it depends on whether you want to run a high CYA pool or not.

Read the Best Guess page linked in my signature. If you keep the high CYA, you'll have to run the chlorine levels shown. It scares some people to run FC that high, though there are no ill effects on outdoor pools that we've been able to discover. And you tend to use less chlorine, and certainly don't have to dose as often with a high CYA / high Cl pool.

Personally, I'd run high CYA, high Cl, rather than dumping all the water. But it's up to you. The 'classic' BBB method I developed assumes lower CYA levels.

You'll either have to run the chlorine levels shown OR lower your CYA. If you want lower the CYA, you'll need to replace 1/2 of your pool water. If you do drain, do so safely. Inground vinyl pools can't be drained without professional help; inground concrete pools in low or wet areas can 'float' out of the ground, destroying the pool. AG pools shouldn't usually be drained completely -- but 6 - 12" of water left is usually safe.

Thanks for your help, been adding acid and PH is starting to drop now with my TA at 150 should i aerate my pool? If yes i have a few questions,the idea is to turn your returns up so they make white water correct? I also use my submersible pump( for my cover), with that pump should the discharge hose be just above the surface making white water like the pool returns or hang the discharge off my kids tree house and make a big splash? Also can i introduce air? I can weight down(deeper is better?) a garden soaker hose hook it up to my compressor and make a 50' bubbler. Or would bigger bubbles be better? I can hook up my bounce house blower to a piece of shop vac hose and blow bigger bubbles just fewer. I don't if any of this is a good idea or not but if the extra pump is make sure you tie it down (i use my ladder) or it will spin like a top and break the wires, itself and maybe the liner. Thanks again for your time and help

The more aeration -- white water -- the faster the TA will drop IF the pH is also low (<7.2). The more violent the aeration, the faster it will drop.

I've stripped 100% of the TA from a heated spa in 10 minutes, using the blower. Of course, you can't duplicate that in a pool.

Ben

I should drop the TA correct? What about making a bubbler? Thanks

Sorry i forgot my PH is still high

I wouldn't worry so much about trying to drop your TA -- just get your pH down to 7.0 - 7.2 and it will take care of itself.

When i first do the test the reading looks good (7.2) but if i leave the solution in the tester after a minute or two the reading goes up again. Is this because i have so much bleach in the pool?

I'm checking on this, but I'm pretty sure your initial reading is correct.

Do you know what your FC (free chlorine) level is?

sorry for not getting back to you sooner but its been real hot in ny so i could only do a little work at night. I have bad asthma so i stay in the ac as much as i can in the day and since my pc is in my basement i didnt want to risk the stairs to reply. Anyway here is where im at i think, using the hth 6way kit(by the way is this kit any good?) TC=15/25(kit only does total CL not FC) PH=7.2/7.5 TA=80 I guess my CYA is around 70/75 i changed a little water since my last reading of 75 but not enough to make a big change. How important is hardness in a outdoor inground vinyl liner pool? when i try that test it takes 8 drops instead of 5 to turn the sample red and 7 drops of the titrant to turn blue. now according to the pool store(they use the strips and scan in into thier computer) shock treatment=1.7 TC=9.8 FC=8.1 PH=7 TA=40 CYA=30 and TH=90 and thier advice is to drain more water. the water dosen't look much diffrent then it did a week or so ago its still cloudy with a green tinge when i brush or vac to waste is see no algae the water looks pretty clean you can almost see the bottom in the shallow end. I added clairifier a few times last week and nothing i can see happened. I think im getting close, but the pool store said water change and no CL for a while what do you think i should do? Last question im not sure if my pump is working 100% it seems to be not pumping as hard(90/95%) i have no bubbles i blew out my intakes and returns checked my impeller which turns easy but squeaks(rubber o ring?) changed the sand in my filter and replaced all gaskets/o rings in my multiport valve the psi guage still needs replacing but i believe it works enough to see a 10lb increase it just seems a slight bit clogged/blocked somewhere. THANK YOU FOR YOUR HELP