Low PH

[SlimJim]

I have a problem I hope someone on this forum will be able to help me with.

First some info on my pool.

We've owned the pool for 11 years. It is an above ground 24' round and 6' deep in the middle. We bought the pool new. Had professionally installed and I've maintained ever since. I test the water with a good test kit but I don't use the test strips.

Now to my problem. At the beggining of the year the pool place said my total alkalinity was way high and had me put 2 gals. muratic acid in the pool to bring it down. Ever since I've battled low PH and low alkalinity. I've never had this problem in the past. After much reading on this forum, I proceeded to raise the alkalinity first by using Arm & Hammer Sodium Bicarbonate. After raising the alkalinity to 90 I proceeded to raise the PH using Borax. The 20 mule team green box Borax. So far I've added 12 pounds, not all at once of course, and the PH has only increased slightly. It's still reading about 6.9 to 7 on the teat kit. The alkalinity has increased to 130. At this rate I'm going to end up with a super high alkalinity rating again. Just like everyone else I'm having a hard time keeping clorine in the pool.

Any advice on what to do? I want to have this problem fixed before time to close the pool.

Thanks for you time and trouble. I know everyone has more important things to do than answer these forums.

[SlimJim]

I guess everyone is as stumped as I am. Thanks anyway.

[pk4217]

your CYA?

[SlimJim]

I forgot to mention CYA. It reads a little high I think. About 100. I took the water in to have it tested by someone I trust and was told to add 2 lbs of PH increaser. I've added 4 lbs and still reading the same. The only thing I can think of is 20 mule team borax is not the same thing as pool store PH increaser, soda ash I believe. I've added a total of 16 lbs borax and little change in the PH. The water is clear and it really sparkles though. Could it be that 20 mule team borax is more of an optimizer than an increaser? I guess my next step is to pay the price for pool store PH increaser and see what happens.

Thanks for asking.

I shocked the pool about 6:00 PM with 4 lbs. of shock. Thats about twice what I normally use to shock it. I just now tested 10:30 PM and the reading is about 1. I reshocked with 3 gal. liquid clorine and will recheck in the morning. I also shocked it with 3 gals. clorine last Thursday. I try to keep three 3" tri- clor tabs in the skimmer at all times. This is the first year I've used the 3" tabs. In years past I used biogard smart sticks. Like I said, I'm having a time keeping clorine in the pool.

I'll repost as I learn more. Keep those ideas coming boys and girls.

[pk4217]

you using stabilized chlorine? change to liquid bleach, which will increase your PH but not TA.

[SlimJim]

Do you mean stop putting the 3" tabs in the skimmer and pour in liquid bleach as needed to keep the clorine level up in the pool? Or, use only liquid bleach to shock instead of calcium hypocloride? Or, maybe both?

Thanks again for the quick reply.

[pk4217]

stop using the 3" trichlor, it'll keep raising your CYA and lower you pH. unless you replace your water, or find a way to drop the CYA.

calcium hypocloride will lower your pH.
so, your only choice for the rest of the season is liquid bleach.

[christian]

I am having this same problem, but have an in-ground pool. My pool is 12' X16', so how much liquid bleach do you think I should use?

This problem is killing me, as I may as well be dumping money into the pool rather than chemicals. Thanks.

[pk4217]

capacity for rectangular pool = length * width * average depth * 7.5 = total gallons.

assuming your average depth = 5', your pool = 12 * 16 * 5 * 7.5 = 7200 gallons.

1oz bleach of 12.5% will raise 1000gallons by ~1 ppm. and 2oz bleach of 6% will be needed for ~1ppm...... so, do the math.

[SlimJim]

Thanks PK4217. That's what I will do.

[walt]

I have a salt water pool with low ph. Any suggestions?
Thanks

[Guest]

stop using the 3" trichlor, it'll keep raising your CYA and lower you pH. unless you replace your water, or find a way to drop the CYA.

calcium hypocloride will lower your pH.
so, your only choice for the rest of the season is liquid bleach.

Cal Hypo will increase your pH. It has a pH of 11.7 and sodium Hypo (bleach) has a pH of 13

Just get a little pH increaser and fix the problem directly. It will be a good fix and you will have it when you require it again. Its cheap and does the job and available most anywhere that pool chemicals are sold.

The Boric acid will help support your pH and may the water feel silky. It will also help raise the pH

[chem_geek]

Cal Hypo will increase your pH. It has a pH of 11.7 and sodium Hypo (bleach) has a pH of 13

The Boric acid will help support your pH and may the water feel silky. It will also help raise the pH

Actually, it turns out that Sodium Hypochlorinte (chlorinating liquid or bleach) or Calcium Hypochlorite (Cal-Hypo) only temporarily raise the pH. The chlorine will get broken down by sunlight or will oxidize organics or disinfect or turn ammonia into nitrogen gas -- all of which are acidic processes. The net effect is no change in pH. Now, chlorinating liquid, and to a lesser extent bleach, do add a small amount of sodium hydroxide (lye) for stability so that will result in a small net increase in pH, but not very much.

Full technical details may be found at Equations for Chlorine Chemistry