IG pool with slight green algae problem

[cindy & jj]

For 8 years, we have had our in-ground 10,000 gallon plaster pool and live in Waikoloa on the Big Island of Hawaii (DE Filter with 1 HP pump/60 gallons per minute). Last May, we painted it with Insl-X paint and we now are fighting green algae. . .we have never had this problem before.

Before we painted it, we used trichlor (FC 3-5) and one cup of acid a week to keep the PH at 7.4 and we fought a little yellow algae in the warm summer months. (Ran the pool about 2 hours a day. . .vacuumed once a week and had to super chlorinate once or twice a month with Cal Hyp but the pool had nice clear water all the time and it was a pleasure to take care of)

Now after painting the pool in May, our pool numbers that I know are:
FC: 3-5
PH: 7.8
CYA: 50
TA: 60

We have tried trichlor, bleach and cal hyp and nothing can beat the green algae growing on some of the walls and bottom. The pool water is a bit hazy all the time unless we constantly run the filter. We have not had to add acid for 4 months according to the test kit (but our TA is really low) and when I use the pool calculator, it says we need to add over 4 lbs of baking soda which we do not feel comfortable doing.

We super chlorinate then vacuum the pool on Sunday but by Wednesday, the algae is growing on the bottom and walls and the water is a bit hazy. Any suggestions on where to start? :?

 

[duraleigh]

Welcome to the forum.

Chlorine will kill algae completely.......you just havent used it in high enough dosages or perhaps not kept it in there long enough yet. The best way to introduce chlorine into your pool is Clorox....it adds none of the side effects that tri-chlor and Cal Hypo do.

Read the "ABC's of Pool Water Chemistry" found in Pool School. Then, read "How to Shock your pool". Both those articles should give you a good grasp of how to permanently fix your algae issues. Follow the shock process precisely which will involve more Clorox than you think, but your algae issues will be over.

What are you testing with?

The baking soda is fine for pools. It is chemically the same as "Alkalinity up" sold in pool stores.

 

[cindy & jj]

Thanks for the tip with the Liquid Bleach. . .

Our test kit is just a basic 5 chemical one from Home Depot.

 

[Bama Rambler]

The first thing you should do is get yourself a good test kit. There's a link to the best one in my sig.

The problem with those HD test kits is that 1) they're not accurate and 2) they don't test all the things you need to test. You'll be surprised how much easier taking care of your pool is with a good kit.

Don't be worried about adding the chemicals recommended by the Pool Calc. As long as you have the targets set correctly it's not going to tell you to add something in any amount that will harm you or the pool.

By the way, a TA of 60 isn't all that low and if you're not having to add acid to maintain pH it sounds like it's just right for your pool.

 

[cindy & jj]

Thanks Bama Rambler. . .already looking at the new test kit. . .and thanks for mentioning that we don't have to worry too much about the TA.

Cindy