[starman]

We have this Intax pool that' 15' wide. It's great for the kids without having the problems if a real pool. The problem is that we've had it for 4 years, always kept it clean, and last August after it rained for three days straight, it got algae. Normally we'd put the algae cleaner in there and that would be the end of it, but this time it's not going away. So I drained it last year and decided that I'll just clean it this year and it'll be fine. Well, this year I cleaned it again, filled it, it rained, and now we again have algae that won't go away. Any ideas?

[Cold Warrior]

chlorine

[starman]

Did that

[Eriamjh]

Make bio-fuel?

[ghporter]

"Shock" it. That's a MAJOR overload of chlorine that is intended to kill everything in the pool. Let it sit and run, so the whole system, plumbing and all, gets thoroughly treated. Keep the chemistry going for a day or three. And keep an eye on the pH so that you don't make it comfy for the algae after you've killed as much as possible.

[Cold Warrior]

like ghporter said -- up the dosage. Nothing living can fight enough chlorine.

[Laminar]

I could.

[mduell]

Algacide

[Dork.]

You may want to get a test kit for a real pool and test the water. There's lots of stuff that can affect algae growth, and sometimes just using chlorine will fix it short-term, but if the water chemistry is off the stuff will just come right back.

I'm thinking maybe the alkalinity of the water is too low, which can cause the pH to go out of balance after a rainstorm, which may encourage the algae growth. That's easy to fix, though: after cleaning the pool out and adding the fresh water, pour in some baking soda. The link may give you an idea of how much is required.

[Railroader]

Originally Posted by Laminar 

I could.

I'll buy the chlorine!

[reader50]

What kind of algae are you running into? The normal turn-the-water-green kind? Or something more interesting, like green/yellow/black on the walls? My answer below (and most of those above) assumes the normal green-water type.

Chlorine is the general answer to algae. However, if the pool isn't responding much to elevated chlorine, then strip your filters down. Examine the elements for small tears.

If tears are present, the filters will be allowing fine particles to remain in circulation. This is useful to algae, and it makes the pool much less responsive to chlorine. You may be able to see this directly as cloudy water.

[wallinbl]

Normal dose of chlorine plus a packet of Stop Yellow or some other such shock treatment. Will generally work after about two days. I'd do that, then after two days add another dose of chlorine.

FYI - every time it rains a decent amount, put chlorine in it immediately.

Also, when adding chlorine, run your pump for a good 5 hours or more afterwards. Do not put chlorine in the pool while the pump isn't running - it won't get well circulated.

[wallinbl]

Don't know if they have them in NJ (one on every corner around here), but most pool stores will test your water for free and tell you what's up.