Water not clearing up

[thewayne]

I have a 20000 gal AG vinyl liner pool w/ a sand filter. My water was clear when removing the cover. However some of the yucky stuff from the cover made it into the pool and i had a algae bloom the next morning. I have shocked and stabilized. My water remains a cloudy blue/green.

My numbers as of today are:

FC 5
CC .5
TA 290
PH 7.2
Cya 25-30

These numbers are after adding a quart of acid and aerating the pool for the past 2 hours. I can see the bottom but not well.

what else should I do?

[KurtV]

Bring your chlorine level to 12-15 ppm (you're in a gray area in the best guess table), test frequently (~3x per day), add chlorine as necessary to return to 12-15 ppm Cl, and repeat this until you maintain that chlorine level overnight.

Don't worry about your A until the algae problem is solved.

[thewayne]

Finally cleared up. However I had to use a quart of poly quat to get there.

I don't know what the deal was. I tested my water 3 times a day and kept the chlorine at or above shock levels for a week and could not get pass the blue/green phase.

So I added a quart of poly quat and over night the pool was magically clear.

I think next year I am going to start with poly quat.

I spent $50 - $60 on bleach and poly quat was only $18.

[chem geek]

PolyQuat is not only an algaecide, but is also a clarifier. It usually doesn't help as much with an algae bloom (especially in the beginning) mostly because it is simply overwhelmed with the quantity of algae. But as a clarifier, it helps clump suspended algae together so that it can filter out more effectively.

What is puzzling is that your pool was stuck in the blue-green phase and didn't continue to gray then milky then slightly cloudy then clear. This sounds like the algae was still growing almost as fast as it was getting killed by the chlorine. Perhaps it was on the "edge" of breaking (i.e. where chlorine kills algae faster than it can reproduce) and the PolyQuat pushed it over the edge, but this would mean the shock level wasn't high enough, which is very strange.

When you tested your water during the week, especially when your pool was "stuck" in the blue-green phase, did the FC level drop a lot overnight or was it fairly stable? This info might help us figure out what was going on so we can give better advice in the future.

Richard

[thewayne]

It had dropped over night the first few nights, but the last couple of nights it only drop by 1 or 2 ppm.

My cya was 0 so I attributed the loss to this, but I am still new to this so I am not too sure.
I have been slowly raising cya during the process.

Now I have to get my TA down, it's at 290.