I thought it might be useful to start a thread for all of us Pentair QuadDE filter owners to share some "best practices" when its comes to cleaning out a QuadDE filter. Jblizzle has a great sticky thread on how to clean a standard grid type DE filter. This isn't meant to replace anything he has written but to add some pictures and highlight some differences between a grid style and a cartridge style DE filter. Since my filter was due for its annual deep clean, I thought I show some pictures off the process. What's listed below is what I do for cleaning the filter, others may have different tricks and tips to share...if so, please do respond!!
How To Start
The first step is to always gather the tools you need for the job. This is what I need based on my filter and the location that it's in. Your list may vary.
7/8" deep pocket socket wrench (I use a 1/2" ratchet handle)
Large flat-head screwdriver
Rubber, wooden or plastic mallet (mine is a plastic mallet used for tent spikes)
Water-proof Silicone lube (I do NOT use teflon based or teflon-added lubes)
WD-40 White Lithium spray grease (only used on the saddle clamp nut & bolt, never anywhere inside the filter)
Large plastic tarp (I use this to direct the flow of water and waste from the drain hole as water causes a lot of erosion around my equipment pad)
Lots of rags (I find old dishcloths work the best)
Garden hose with good pressure!!
Bar-Keepers Friend liquid cleanser (more about this later)
1.Since my filter always has water in it (a check valve keeps it from draining), I always start by backwashing the filter. This gets rid of a good portion of the DE from inside the filter and makes cleaning out the filter body a little easier.
2. After backwash, I cut the power to all pumps. I leave the backwash valve in backwash position and open the high flow bypass valve (HFB). This will cause all of the water in the filter above the level of the input coupling (the one on top) to drain out through the backwash line.
3. After the filter drains, I remove the saddle clamp by undoing the tension bolt assembly (7/8" socket wrench required). I sometimes spray some of the lithium grease on the threads to help the bolt move smoothly.
4. With the saddle clamp removed, I lift off the top lid and put it aside (this is heavy and, if you can't lift more than 50lbs, you should get help). Once the lid is removed, this is what I find -
5. I then open up the drain plug on the bottom of the filter and let the remaining water (and some spent DE) drain out. I lay out the tarp so that the flow from the drain plug is directed down the rip-rap embankment so as to not cause soil erosion (my equipment pad is in a lousy location some day I will need to build a very big and very expensive block retaining wall and buy A LOT of fill sand to replace what erodes away).
6. With my garden hose, I rinse as much of the muck off of the cartridges as possible allowing all the muck and spent DE to drain down the tarp. I remove each cartridge one at a time and continue to rinse out the filter body.
7. Pentair uses an internal, stainless steel ring inside the filter body to aide in the saddle clamp having a stronger circumference to seal against. You can see a small amount of corrosion-
I use the BKF cleanser and a soft sponge to clean away the rust stains. Why BKF you ask? Because it's just silica grit polishing compound with oxalic acid in it. The oxalic acid is very good at chelating and removing rust stains. This will all be rinsed away as I continue to clean and remove cartridges.
8. At this point, the filter body and bottom flange assemble are clean -
I'd like to take this time to point out that Mark (mas985) was right about the fact that the input of water into the filter under normal operation is actually diverted downwards and towards the lower wall of the filter body to create lots of turbulence so that any DE that settles at the bottom is easily stirred up. The Pentair Owner's manual does not show it that way (it shows it pointing upwards) so it's nice to see that they designed the filter input with turbulence in mind.
9. Now the "fun" part, cleaning off the cartridges At this point, I go to the back wall of my property with my garden hose and a bucket or pail turned upside down so that the filter can be held upright on it at a level that means I don't have to bend too much. Cleaning takes A LONG TIME as the DE is all entrained on the filter cartridge surface with every form of organic and biological nastiness. It's basically a goopy muck of human bather waste, leaf litter, hair, bugs, decomposing and oxidized organic compounds forming a zombie-like flesh on the cartridge surface.
Pro-tip #1: Wear long pants, and a long sleeve shirt, preferably clothes you don't like too much...and then be sure to WASH THEM right away after you are done....
Pro-tip #2: KEEP YOUR MOUTH CLOSED! (don't ask how I know that )
One down, three to go -
Now those are some nice-looking cartridges -
Just a note on removing and replacing the cartridges -
>>The top black flange fits snuggly into the holes in the top of the cartridges. Sometimes it helps to take a large, flat head screwdriver and VERY VERY VERY GENTLY pry it up a little bit....did I mention being GENTLE!!! Also, in the middle of the top flange assembly is the spring that the cover pushes down on and the air-bleed tube with the metal mesh top cover. If the mesh looks bent and flattened down, that is TOTALLY NORMAL. The mesh gets coated with DE and is only there to be an air bleed for the filter to keep large air pockets from forming in the top of the filter. Be careful with all of those parts, clean and replace them.
>>When putting the black top flange back on, I find that I need to use my mallet to VERY, VERY, VERY GENTLY tap the flange back onto the cartridges so that they seal up nicely....did I mention being GENTLE??
10. Clean up the filter body o-ring using water and rags. Re-apply a necessary amount of silicone lube (all that is needed is a thin layer) and re-install the o-ring.
11. Remove the High-Flow Bypass from the top of the filter body by unscrewing it (careful, there is a rubber grommet there to act as a seal). The HFB valve looks like this -
12. Disassemble the valve by making sure it is the open position and then GENTLY push on the two side tabs to split it apart. Some force may be required -
13. Clean the valve body and twist flange. Those two o-rings are standard sizes that can be found at any hardware store (I get replacements at Ace Hardware). They can get coated with DE and worn down over time. I usually have to replace them every two years or so. I remove them, clean them off and then re-lube them. It makes opening and closing the HFB valve easier.
14. Clean out the top body assembly of the filter, replace the HFB valve and reassemble the filter. Be sure that the drain pug has been replaced (hand tight is fine).
15. The saddle clamp bolt and screw should be cleaned off with a rag and I like to lube the bolt and screw with white lithium grease. None of that should ever be sprayed directly into the filter body. The saddle clamp bolt should be tightened down with your ratchet until the anti-backlash spring is fully compressed (no gaps between the turns of the spring.
16. Put the backwash valve into the filter position (normal operating position), open the high flow bypass valve and start up the pump. At this point you should hear lots of air hissing out of the HFB valve. Keep running the pump until all the air is out of the filter and water is flowing ("gushing like a fire hose" is a better description) out of the HFB valve. Close the HFB valve, let the filter pump run. Note the clean, uncoated filter pressure.
17. Follow you standard recharge procedure for the DE filter. I only recharge my filter with 10lbs of DE at startup. When I do backwashing (which is only at most 3 times per year), I only use 4 lbs of DE to recharge after a backwash and not the full 10lbs again. Using that much DE is overkill as backwashing typically only removes about 50% of the DE at best. Please follow whatever is your normal procedure.
Hope this helps and please respond with any additional tricks YOU have learned over the years.