DE filter: backwashing vs. draining

[ddas]

I'm new to this. When I took control of my pool a few months ago, I drained the DE filter, disassembled it, and thoroughly hosed it down before reassembling it. Then, because DE irritates my skin, I replaced the DE with cellulose.

This week I had a minor algae outbreak, so I had to use a lot of extra chlorine, and I understand I need to clean the filter. (And the filter pressure is up by about 10-15% over normal.) Should I backwash it or disassemble it? What's the difference? Why would someone do one vs. the other? (I assume backwashing should be a lot faster.)

(Part of me would like to disassemble it so I can see the cellulose on the filter grids so I can see how well they got covered and if I got the quantity right. I still have no concept of whether the cellulose is performing better/worse than the DE...if I put in enough at all.)

 

[danacc]

You don't need to do anything until the pressure is 25% over the baseline set when it was clean.

When it is over 25%, you just need to backwash it. You're right that most folks don't do a disassemble and full clean each time the pressure reaches the threshold because of the extra effort and time involved to do this. You will get it clean by backwashing and adding fresh cellulose. Eventually, the pressure rise may start happening much more quickly even though there is no obvious cause (algae in the water would be an obvious cause). This is the most common indicator that a disassemble and full cleaning is in order.

 

[ddas]

Oddly at the peak of the algae outbreak and containment, the pressure was about +20%. And now it's back to +5%, about 6 days later. This concerns me that the algae (dead) is finding its way back to the pool.

Maybe I didn't add enough cellulose...?