Hey Ben,

You helped me many years ago as I was building and starting my pool. I guess now I’m having ‘old pool’ problems as the pool is now 16 years old. I have an in ground, gunite fresh water pool using only chlorine and muriatic acid to balance.

My issue is with my filter which is an old Pentair SMBW 2060 using DE. Water is dripping out of the back flush pipe while the pump is running and when it shuts off, it draws air back into the filter. If the air isn’t bled out at next filter cycle, when it starts I get huge bubbles pushed into the pool until is settles down. I think with all that air in the filter while pump not running reduces the effectiveness of the DE and I have to change out the DE sooner than normal. I’ve never backflused in 16 years, always complete disassembly and flush with fresh water, grids and all.

For the moment, I’ve capped the backflush drain with a threaded fitting so I can clean out the filter body when needed. I don’t know if this will affect the filter operation or not. It seems the backflush valve at the base of the filter may be bad but I here they’re tough to change.