Sand filter failure

[Old Eagle]

I believe you on the NO for the liquid cover. I can imagine it fouling the sand. Thank you both Watermom and Carl.
Another question: What about the idea of putting a limited amount of DE media on top of the sand in my sand filter? I have not done this, but it sounds logical when you think of the very fine particles that cloud a pool and keep going through the sand filter. In past years I did have good results using a clarifier solution to make the fine particles stop going through the sand filter. Now I am scared of adding anything but bleach and chemicals to adjust the PH.

[CarlD]

Both WaterMom and I, and many others have added DE and the results are excellent.
Record your pump's pressure (on high if a 2 spd or VS) apnd keep it running.
Add 1/4 cup of DE and wait 20 minutes.
Wait, oh 20 minutes and see if the pressure has increased by 1pound, if so you are done. If not, add another quarter cup and wait again repeat until you reach one pound increase in preassure.
If you go over more than two punds, just backwash it out and start again. Try 1/3 cup this time.
Once you find the right amount, which will be between 1/4 cup and one cup, just add that much everytime after you backwash.

That's all there is to it!

[Old Eagle]

Thanks much! That sounds like a very good plan. I had not thought about the backwash pulling the DE out but I guess that really will remove it. I am guessing that you put the DE in at the skimmer, but maybe at the pot just before the pump. I suppose either will work and the skimmer would be easier.

[CarlD]

No, no, it MUST be in the skimmer while the pump is running! You have to shut down the pump and shut off valves to open the pump's skimmer pot. Then it probably will clog and not distribute properly.
Don't make things tougher on yourself than you need to!

[Old Eagle]

Carl, Thanks again for all your very good advice.

[Old Eagle]

Carl,
Your advice on how to use some D.E. in the sand filter works great. The cloudy stuff in my pool is being caught at a high rate. I had to use a fairly large amount of the D.E. to get the 1 pound rise in pressure you suggested. I think that is because my filter has a large amount of surface area which needs a coating to get the pressure rise. That surface area is about 1000 square inches.

One certainly does not need a water clarifier when you use your D.E. method.

I have noticed an interesting thing happening so I will report it here. When I put in the D.E., check the pressure, and then start up my Kreepy Krauly, I think the pulsations of the Kreepy Krauly cause the D.E. to disappear, probably passing right on through the sand and back into the pool. The small amount of D.E. would not be noticeable in the pool if that is what happens. It may be that the D.E. disappears because I have a yet-to-be-found air leak in the return line that causes the filter pump to sort of cycle up and down in pressure as it grabs the air and then grabs more water. I have yet to locate the return line leak but I know how to do that and will fix the leak as soon as I do.