Stabilizer ?

[hannadock]

Should I get my stabilizer up before trying to add bleach?
My PH is around 7.2 and alka around 30. Presently my pool has algae on the entire bottom. I just took the cover off today. I put 3.75 lbs stabilizer into skimmer. I have a 20x40 inground with around 36000 gals. thanks

[Watermom]

No. I wish you hadn't added that stabilizer yet. Actually, we usually advise people to forget about the stabilizer while they are fighting algae. While you are trying to clear your water, you are most likely going to be vacuuming and probably backwashing often. (Backwash whenever the filter pressure goes up by 8-10 psi over your clean filter pressure.) Stabliizer (cya) dissolves really slowly in your filter -- maybe even up to a week. So, if you backwash in that week, you end up throwing out the stabilizer.

[polyvue]

Should I get my stabilizer up before trying to add bleach?
My PH is around 7.2 and alka around 30. Presently my pool has algae on the entire bottom. I just took the cover off today. I put 3.75 lbs stabilizer into skimmer. I have a 20x40 inground with around 36000 gals. thanks

Alkalinity seems a bit low... but I agree with Watermom -- fighting algae is the priority. The good news is that 3.75 lbs of dry stablizer should only increase CYA ~ 12 ppm in your 36K gallon pool. But that means you'll need a bit more chlorine to defeat the algae. Refer to the Best Guess CYA Chart to determine the right amount of chlorine. Used in conjunction with the Pool Calculator it's almost easy.

[hannadock]

So forget the chemicals for now and vaccumn?

[Watermom]

Yes. Other than the bleach. Concentrate only on fighting algae now. Other things can wait. Try and test your water several times a day and each time, hit it with some more bleach. The sustained chlorine level is what kills algae.

BTW -- in case others are reading this post. If the PH had been below 7.0, we would have not waited to work on raising that. Low ph is acidic and can damage a pool. But, since the ph in this case is 7.2, that isn't an issue. All other chemical needs are not a priority right now.

[chuck9997]

I am in the start up process now.. first day. I have added bleach.. and more bleach. Been checking the Chlorine level.. Had it up to about 15ppm.. a few hours later checked and it was at 4ppm. Is it normal to drop that much in a few hours?

I failed to check the PH before adding the bleach.. can I still get a true PH reading with CL level high? Right now the test says PH is over 8.. but the CL is high.

In past years... never had any problems getting the Chloring up.. and maintaining it.

[chem geek]

I failed to check the PH before adding the bleach.. can I still get a true PH reading with CL level high? Right now the test says PH is over 8.. but the CL is high.

A high chlorine level can lead to a falsely high pH reading so you'll have to wait for the FC to get below 10 ppm before getting an accurate pH reading. The chlorine itself temporarily raises the pH, but the high FC level also bleaches out one of the two dyes in the pH test causing it to typically be misread too high. Taylor talks about that in their Pool & Spa Water Chemistry booklet:

FALSE READINGS: high levels of chlorine (usually >10 ppm) will quickly and completely convert phenol red into another pH indicator (chlorphenol red). This new indicator is a dark purple when the water's pH is above 6.6. Unfortunately, some pool operators mistake the purple color for dark red and think the pool water is very alkaline and wrongly add acid to the pool.

When a sanitizer level is not extreme, only some of the phenol red may convert to chlorphenol red. However, purple+orange (for example, pH 7.4) = red. This error is more subtle as no purple color is observed and the operator does not suspect that a false high pH reading has been produced. Some operators neutralize the sanitizer first by adding a drop of chlorine neutralizer (i.e. sodium thiosulfate). However, thiosulfate solutions have a high pH and, if heavily used, may cause a false higher sample pH.

The Taylor pH test has some special chlorine neutralizers in it such that they don't affect the pH very much, but even these don't work at very high FC levels so generally you can't trust the pH test above around 10 ppm FC.

Richard

[Watermom]

Chuck -- if you continue to need some help with your pool, why don't you go ahead and start a new thread of your own. It is best to do that instead of tacking on to somebody else's. Sometimes trying to help work on two different pools within one thread gets too confusing to follow. Glad to see you back around the forum!

[hannadock]

Thank goodness I finally got back to be able to post. Ok. I have added 18 188oz bottles of bleach and scrubbing the floor and walls. 30 X 40 pool with around 36000 gallons+. Dumb question, I can't see what I am vacuuming. Is all this bleach suppose to clear up the water so I can? I started vacuuming on waste but I couldn't see if I was doing any good yesterday.

[Watermom]

Yes, the bleach will clear up the water. As it kills algae, your pool will get less and less green, although the dead algae often clouds up the water. Is there any debris on the bottom of the pool? If so, net it out. If not, just keep socking it with bleach for now and backwashing whenever your filter pressure rises 8-10 psi over your clean filter pressure.

How many times a day are you testing your water? You need to do so at least twice (and 3 times) per day is even better. Each time, add more bleach. The key to killing algae is to sustain high chlorine readings. If you don't, it will take forever to clear the pool. You don't want to shock it and then let it fall way off before dosing it again with more bleach. Keep us posted on how it is going.