Reduce Total Alkalinity Levels

Problems relating to pH and total alkalinity.
Increase ph, increase TA. Reduce pH, reduce TA.
pH chemistry advice and techniques for the pool.
MisterBuddy

Reduce Total Alkalinity Levels

Postby MisterBuddy » Wed 08 Jul, 2009 16:19

Just found this thread, very interesting... I've never heard about aeration before but it makes a gut sort of sense. My particular situation is TA of 170, ph 7.2, Hardness 230 in an OLD gunnite pool having more in common with a lake or sound than with what we ordinarily visualize in terms of swimming pools. But enough about me. My situation is far from dire, but I wanted to share an idea I had for aeration: use a small electric air compressor and a soaker hose for dispersing the air in the water. Obviously you don't want to over-pressurize the hose, and it is going to be a trick to actually sink the hose and keep it down, but I can see skads and skads of tiny bubbles as the result.

Great thread, great forum, I'll be back. (I am also a member of the Pool Forum.com) Peace.


Guest

Reduce Total Alkalinity Levels

Postby Guest » Tue 14 Jul, 2009 08:20

What should I buy to reduce the ph in my above ground pool 16x48. It was fine until it rained the other day, then it turned really green so I started adding lots of chlorine then It was really cloudy light green, its just messed up and I don't know what to do to get it back clear. please help.
iris

Reduce Total Alkalinity Levels

Postby iris » Thu 16 Jul, 2009 13:20

20 Mule Team Borax is a laundry additive that's been around for ages. You can usually find it in with the laundry cleaners at most larger grocery stores and possibly WalMart stores.
chem geek
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Reduce Total Alkalinity Levels

Postby chem geek » Thu 16 Jul, 2009 19:27

Borax will raise the pH, not lower it. Muriatic Acid or dry acid (sodium bisulfate) will lower the pH.
Green Pool

Reduce Total Alkalinity Levels

Postby Green Pool » Sun 09 Aug, 2009 13:56

Alkalinity shows off the charts (high) while, PH is extremely low. Nothing seems to work.
barbados

Reduce Total Alkalinity Levels

Postby barbados » Fri 21 Aug, 2009 11:52

Hi, All! I found help here, my day is improving!

Please help a dumb engineer understand this pool chemistry stuff:

*15,500 gallon in-ground gunite pool 30 years old.
*pH is always 6.8 or below so we've been adding lots of buffered soda ash but it doesn't seem to increase pH
*White staining on dark pool sides
*Green algae patches here-and-there even with correct chlorine, brushing and aglecide weekly

OK, I just checked TA for the first time in years and it's 130. pH is below 6.8

Do i understand correctly that I must add acid to lower the TA?

Haven't had much free time to read this total thread, but the blurb in my test-kit booklet states "Do not add acid if the pH level is below 7.6 to correct TA" Huh? :crazy:

HELP! :roll:

-dave-
chem geek
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Pool Industry Leader
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Reduce Total Alkalinity Levels

Postby chem geek » Fri 21 Aug, 2009 12:05

Dave,

In your case since the pH is already low you just aerate the water to raise the pH first and then add acid to lower both pH and TA. HOWEVER, if your pH is very low then why are you wanting to lower your TA in the first place? I suspect you are using Trichlor tabs/pucks which is causing your pH to be low and suspect you are adding baking soda (what do you mean by "buffered soda ash"? Soda ash is sodium carbonate) which is having your TA be high but not your pH. When your pH is low, you can add pH Up (soda ash) which will raise both pH and TA or you can add 20 Mule Team Borax which will raise the pH and only raise the TA half as much. Since your TA is already up, then the 20 Mule Team Borax would be better or significant aeration. Another alternative is pure lye (caustic soda), but I don't know where you could get that and you'd need to pre-dilute it in a bucket of water.

You should realize that continued use of Trichlor (or Dichlor, for that matter) will increase the Cyanuric Acid (CYA) level over time making chlorine less effective and that you can get algae if you don't use a supplemental algicide or phosphate remover (at extra cost). Read the Pool School for more info on maintaining your pool.

If you stop using Trichlor pucks/tabs and switch to chlorinating liquid or bleach, then with aeration your pH should rise. I am concerned, however, about how low it really is since 6.8 is the lowest measurable on most pool test kits.

Richard
barbados

Reduce Total Alkalinity Levels

Postby barbados » Fri 21 Aug, 2009 12:55

Thanks so much for the quick reply, Richard!

Yes, I have been using 3" trichor pucks for years but, now that you mention it, my problems started with the use of a 50# sack of buffered soda ash from our industrial chemical supplier. Probably incorrect, yes?

I have access to all industrial chemicals and sodium hydroxide comes to mind (12-14pH, yes?) Would this work in place of lye or Borax?

Should I discontinue the use of the trichor and move to ??

At this point, what would be your move?

You help is sincerely appricated! :D

-dave-
chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2382
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

Reduce Total Alkalinity Levels

Postby chem geek » Fri 21 Aug, 2009 20:09

Sodium hydroxide is lye. It's rarely used in pools since normally the TA gets low along with the pH when using Trichlor. I really don't know what "buffered" soda ash is -- regular soda ash is just sodium carbonate. Anyway, if you are fairly sure of your test results because you yourself have tested it with your own good test kit, then you could use the sodium hydroxide but note that it doesn't take as much by weight to move the pH. Roughly speaking, 1 pound of sodium hydroxide is equivalent to 2.6 pounds of soda ash.

I strongly suggest you get your own good test kit, either the Taylor K-2006 you can get at a good online price here or the TF100 you can get at tftestkits.net here with the latter kit having 36% more volume of reagents so is less expensive per test.

If you have only been using Trichlor, then your CYA level may be high and if it is then you are lucky you don't have algae growth. What you do is up to you, but it's less expensive to maintain the pool using chlorinating liquid or bleach, but it's less convenient since you need to add chlorine every day or two unless you have a pool cover (then twice a week addition) or an automatic dosing system (The Liquidator, or a saltwater chlorine generator, SWG, system). If you want to continue to use Trichlor, then you should consider diluting the water to keep the CYA in check and/or use a supplemental algicide (PolyQuat 60) or phosphate remover to try and keep algae at bay, though as you have seen even with weekly algicide you can still get algae if your FC/CYA ratio is too low (due to CYA probably being very high in your case). Again, read the Pool School for more info.
barbados

Reduce Total Alkalinity Levels

Postby barbados » Fri 21 Aug, 2009 21:23

Thanks, Richard,

I'm going to read the pool tutorial and buy one of the GOOD test kits, make some ACCURATE measurements and get back to you.

Thanks for being here for us.

-dave-

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