Bleach

[poser]

I am trying to use household bleach to super chlronate my pool because of a terrible green algae outbreak. My problem is that after I balance my pool and start adding the bleach my TA quickly goes from 110 t0 145-150. Is this to be expected when I add bleach for shock?

[aylad]

Depending on how you're testing, the high chlorine levels can be affecting your test. If you're trying to clean up an algae bloom, don't worry about the TA for now, you can always tweak that after the fact if you need to. Just worry about using an accurate CYA level to determine the bleach dose, and then getting the chlorine level up to the appropriate level and keeping it there until the algae is gone. Run the pump 24/7, clean the filter as your pressure indicates, and brush the pool daily.

[poser]

Since my cya is 100 I would like to stop the trichlor tabs and start using bleach but the bleach seems to raise my TA out of limits quickly. Can someone tell me if this is normal?

[chem geek]

Are you using test strips? A proper test kit such as the Taylor K-2006 will rise in TA when the pH rises which happens somewhat when bleach is added, but not by much. Even at very high Free Chlorine (FC) levels, the TA test still works properly though may go from yellow to blue instead of from green to red.

[Watermom]

Is your pH pretty stable? if so, don't fret too much over TA.

[waterbear]

Bleach does not raise TA BUT high sanitizer levels can cause interference to some tests in some kits and give false readings. What kit are you using? If you are using strips they are just not reliable. What are you doing to "balance your pool" before adding bleach?

[CarlD]

Yes, whenever I hear or read "balance" in regard to pool water I get nervous for the pool owner.
What does "balance your pool" mean, exactly?
What are you adding?
Why are you adding it?
What's in it?
What's its generic name?
How are you determining how much to add?
How are you measuring the result of what you added?

We just need more info,

Carl

[poser]

By "balance my pool" I mean that I get my ph within limits for a gunite pool with tinted plaster (7.3-7.8) and I get my alkalinity within limits (80-120). I have no control of my cya being high except to try and use bleach instead of trichlor but it goes back to my original question about my TA going up quickly when I use bleach at shock level (8.0-15.0). I use muratic acid and 20 Mule Team Borax to balance. I have a Taylor K1005 test kit. I add small amounts of acid or borax and test again and go from there. I don't want to have to rebalance my PH and TA every time I use bleach.

[CarlD]

High FC can cause false high pH readings. I don't know if it also can generate a false high TA.

Meanwhile, when you say you adjust TA, are you doing it by our ratchet-down, aeration method? You lower pH with acid to about 7.0. Then aerate to raise pH without raising TA. Repeat when pH is back around 7.5 until TA is where you want it.

If you aren't doing it this way, you aren't lowering TA...so I'm wondering if that's it.

Carl

[aylad]

And just to add one more comment--shock level for a CYA of 100 is 25 ppm. The normal, baseline, everyday chlorine levels for a CYA that high is 8-15 ppm. If you've been keeping your chlorine below 8 ppm, that's why you keep getting algae.

See the "best guess" chart linked in Watermom's sig for more info....

Janet