DE amount after backwashing

[michelleca]

I have a Hayward 4820 DE filter that requires 6lbs upon start and 4.8lbs upon backwashing, but how can I know if I am adding too much DE after backwashing? Adding DE seems to be more of an art than a science. I add 4.8lbs, or at least what I believe to be 4.8lbs, but more often than not, I lose water pressure and I think I may have added too much DE.

Additionally I'm having my yearly catkin/pollen problem and I believe the filter is getting gunked up with pollen (this is a problem I may post in another thread).

 

[Richard320]

There's a good chance you aren't backwashing 80% off, so when you add 80% back, you're overloaded. An extreme case of what can happen is here. This is after they removed the lid.

cloggedfilter.jpg

• Richard320
• Apr 11, 2019

So..... how handy are you? If you're ready to try opening up the filter and manually cleaning it, you'd know you got 100% off and you can recharge with 100% An annual teardown is pretty typical, and backwash the rest.

One other thing to consider: if your pool is green or cloudy, having a DE filter load up in an hour or two is quite normal. That's the curse of the DE filter.

Additionally, if you have gobs of pollen and stuff, stretch a knee-high nylon over the basket. It will catch a lot of crud and spare the filter. Check out the pictures, Skimmer Sock/Nylon Illustrated

 

[michelleca]

There's a good chance you aren't backwashing 80% off, so when you add 80% back, you're overloaded.

So..... how handy are you? If you're ready to try opening up the filter and manually cleaning it, you'd know you got 100% off and you can recharge with 100% An annual teardown is pretty typical, and backwash the rest.

One other thing to consider: if your pool is green or cloudy, having a DE filter load up in an hour or two is quite normal. That's the curse of the DE filter.

Additionally, if you have gobs of pollen and stuff, stretch a knee-high nylon over the basket. It will catch a lot of crud and spare the filter. Check out the pictures, Skimmer Sock/Nylon Illustrated

I actually did open the filter in the beginning of the season and clean it with the hose, but after backwashing several times already I can't get a handle on whether or not I'm backwashing 80% or not. I backwash then rinse three times. The water in the sight glass appears to be clear by the last backwash, but maybe I should do it a fourth time? The problem is that in order to get the water flowing better a day or two after I last backwash, I'll run 1 backwash cycle. I'm sure I should not be doing this, but I'm getting so frustrated. After reading your response, I realize that I may need to backwash a lot more frequently, like every other day, ugh.

 

[DanF]

You should backwash when your filter pressure is 25% higher than your "clean" pressure - the pressure after you take a part the filter and clean off the grids. For example, my clean pressure is 12 psi, so I backwash at 15 psi.

I believe your filter is a 48 square foot filter. The rule of thumb for DE is 1 pound for every 10 square feet at startup - so 5 pounds at startup, and 80% of that when backwashing in between, so 4 pounds.

Hope this helps and good luck.