Pentair Quad DE 100 - cleaning question

[stever]

Thought I'd ask a questions that's been bugging me for 6 months:

I have a Quad DE 100 filter (see rest of specs below) and have just cleaned it for the beginning of the season (and because the landscape work is finished -- so the daily shower with dirt is over). I figured it would be pretty bad, so I did not backwash it, but rather drained it down, opened it up, and cleaned the grids with a hose. I typically will open the drain-plug at the bottom, disconnect the in/out screw fittings (to the slide valve) and take the whole thing out for a good cleaning.

When I look at the bottom of the filter case, there's 3-4 inches of DE there. After the top half inch or so, it's pure white. It's never been used, re-curculated, on grids, etc. It calls for 10 pounds on full re-charge - so I'm putting the correct amount in....

Also, hard to say if any DE is on the grids, but I assume it'sjust supposed to be a thin layer that can't be seen (with all the dirt on the grids).

Pool looks clean enough, so must be working, but ...??? Should I be putting less DE in? Is this just normal for a bunch to go to the bottom while the grids are being coated? If I decide to backwash next time, I am afraid that this cake of DE at the bottom would remain there.

On a side-note: the filter breaks down quite well and the grids hose off easily.

Thanks,
Steve

 

[PoolDad2]

I have a Quad D.E. 60 and as well think that the amount that is required to charge the filter is too much. This year it didn't fill completely up with D.E. like it did last year. I also flushed it a few times using the drain when I backwashed it. That seemed to help keep the fallen D.E. from collecting on the bottom.

It does break down easy enough and cleans off fast. I did put less D.E. in this past year so that must have helped with the build up of D.E. in the bottom of the filter as well as all I have done along with that.

I called Pentair up and they said that the amount that is stated for the filter in the owners manual is the correct amount. I just think it is a little to much. Also how are you charging the filter. I just put the D.E. in the skimmer and let it suck it to the fitler. I don't premix it with water.

 

[JasonLion]

You want to run the pump on a fairly high speed while you are adding DE to make sure the cartridges get properly coated.

Another possible issue, if you ever backwash without doing the full open up and wash the cartridges you describe, is accidentally adding the full amount of DE after a backwash. Remember that a fair bit of the DE stays in the filter when you backwash, so you only add 80% as much DE. This doesn't apply if you always open it up and wash off the cartridges.

 

[stever]

Thank you PoolDad and JasonLion,

There must have been be 3 pounds (out of the 10) of clean DE at the bottom. This time I put the pump at 65 gpm when addind the DE. I don't remember what speed it was on last time it was changed.

Jason -- you're right about the backwash, though I had not backwashed it since the last cleaning (it's so easy to clean out -- especially if I have to clean out the seperation tank after backwashing!)

I added the DE dry to the skimmer about a quarter pound (or less) at a time. Takes about 20-30 minutes to add 10 pounds. I just shake a little in and wait until it gets sucked into the vortex. SOmetimes a little chunk drops in and I'll wait until it disolves from the bottom of the skimmer basket.

Does the DE fall off the grids when the pump turns off? I expect some does, but hope most stays on. I run at 15 gpm for 4 hours (cleaner running at night), 25 gpm for 8 hours and 35 gpm for 3 hours (spillway to circulate the spa).

Thanks,
Steve