Milky water

[chastclark]

Hello,
I will be greatful for any suggestions on how handle my milky water problem. I cannot see more than a foot below the surface. It all started when I had to replace my pump motor. I was using a 1 hp with a Hayward S180T sand filter. I replaced the motor with a 1 1/2 hp two speed motor. There was about two days of down time while I was dealing with the pump problem.
I have tried shocking the pool with 6% chlorine bleach but the problem has worsened. I even changed the sand in my filter, to no avail.
My current readings are as follows: FC = 21, CC = 1.5, PH = 7.5, TA = 70, CH = 140 and CYA = 115. My tests were made using a TFTest kit. I don't trust my CYA reading but it is in the 100+ range.

A/G round 24' pool 14000 gal., 1 1/2 hp pump and 18" sand filter.

 

[dattia]

With a CYA of over 100, I would imagine that you are nowhere near your shock level, even at 21 FC. I think the best way to clear your pool is to do a partial drain and refill to get your CYA to a more functional level... or ramp up the amount of chlorine to bring your pool to the actual shock value.

 

[duraleigh]

I think the best way to clear your pool is to do a partial drain and refill to get your CYA to a more functional level.

You won't get advice much better than that. (Shock value for 100+ CYA exceeds 40ppm of chlorine!!! )

A more functional level would be right at 50ppm, which would involve probably two separate partial drains and refills.

 

[chastclark]

Thanks for the advice. I'll try the drain and refill and then shock it again.

Charlie C.

 

[chastclark]

Do either of you have an idea of the ratio of water to CYA or how much water I need to drain to reduce CYA to a managable level?

 

[Bama Rambler]

You can use the Pool Calc to figure out how much to drain but with a CYA of 100+ it's going to be at least half. You should aim for a final CYA of 50 ppm as Dave said.

 

[Suziqzer]

It's hard to say since testing only goes to 100 anything above that just reads 100 so your CYA could be 100, or could be 150.. hard to say. You could dilute your pool water by 50% and try the test and maybe get a better idea of your current cya before you partially drain.

 

[lightingguy]

Sounds like you had a small algae bloom (very common with high CYA) that really took hold when the pump went down.

When you elevated your FC you killed off a good chunk of the algae and that caused your water to cloud up even worse. Again - exactly what you might expect.

Once your CYA is down to a manageable level you'll be in a better position to properly shock the pool. The point there is to kill of ALL of the algae - not just 90% of it. Once it's all gone - as long as you maintain your FC at the proper level for your CYA the algae will never be able to get a foothold again.