community pool just does not get clear!

[Stierchen]

The pool belongs to a home owners association and I am a home owner who takes care of it. The pool is L-shaped and holds approx. 38,000 to 40,000 gal. of water. It is not open right now. We just bought 25 pounds of DE. I have never worked with DE but assume you put it in the sand filters. Correct? If yes - we will put it in this afternoon, because I need some help doing this.

[PoolDoc]

Do NOT put it directly into the filters!

Instead, put about 2 quarts -- 1/2 gallon -- of DE into a skimmer while the pump is ON. Then, go watch the return jet closest to the filters. If DE shoots back into the pool, your filters need service. If not, the DE will help filter fine particles, but will likely cause the pump pressure to rise much more quickly, so you may need to backwash in much less time than usual.

You'll still need the kits . . .

When you wrote that the "pool just does not get clear", did you mean just this spring, or normally?

Also, what chemicals and processes have you used trying to clear the pool this spring?

[Stierchen]

I ment only this spring it does not get clear. In the 20 years that I lived here they always drained the pool completly and started with fresh city water. This year we wanted to see if we can turn it from swamp to clear for the first time. After I have spent endless hours working on this (approx. 2 per day) I will not do it this way ever again. The electricity to run the pool 24/7 cost the same as new clean water. All the chemicals I have used so far are mentioned in #4! No I am starting with the DE.

[PoolDoc]

Cleaning up swamps can be uneconomical. In years past, when I serviced multiple very large commercial pools, I'd sometimes have to clean a swamp. Usually, I'd dump 3 - 4 gallons of 15% industrial bleach for every 10,000 gallons of pool water (30 - 50 ppm). It would turn gray within an hour and cloudy blue within a day.

But I was buying fresh bleach at ~$0.50/gallon. That was MUCH cheaper than any form of chlorine you or most pool owners can buy.

Test with the DE; give me what test results you've got; tell me what color the pool is; and ORDER the K2006!

One really important point: killing algae is much easier with one very large dose of chlorine, than with 4 smaller doses. The small doses allow the algae to recover, and tend to be wasted.

[Watermom]

You should be able to keep it clear over the winter. I always keep my pool open as long as possible so I can keep adding chlorine until the nights start having below freezing temps. Then, I open it early in the spring. My water is always clear. I do not cover my pool in the winter and do have a little dirt in the bottom in the spring, but that is easily vacuumed up.

[Stierchen]

Last night we put the DE into the skimmer, but we can't see the returns at the bottom because of the cloudy water. Nothing came to the top - does that mean the filters are OK? We had to backwash within 1 hour of adding the DE. The pool does not look any clearer today. Does the DE go away with backwashing? Should we keep doing this again?

[PoolDoc]

If you can't see the water stream from the returns . . . it doesn't tell you anything. The DE is either on top of the sand in the filter, and will be backwashed out OR it's sitting on the bottom of the pool along with the dead algae.

*If* the DE is on the filter, you should see filter pressures rise much more quickly than normal. If this is not happening, I'd recommend opening one of the filters and checking sand levels.

Something just occurred to me -- if someone has backwashed the filters one at a time, instead of doing both simultaneously, odds are you've blown much of the sand out of the filter. I'm guessing the flow curve below shows your pump on the "F" curve. If so, that pump will deliver WAY too much water, during backwash, for a single filter. Maximum backwash flow on a TR-140 is about 110 GPM. That pump can deliver 2x that rate of flow.

If the standard practice at your pool has not been to backwash both pumps simultaneously, you'll need to (a) replace the missing sand and (b) develop a process that will ALWAYS be followed during backwash, in order to prevent excessive backwash rates.

[PoolDoc]