Pool Startup -- Algae + DE filter

[bjb1966]

Yes it does seem to be upon turning on the pump. This morning I turned it on to recirculate again and just a little bit came out of return and then cleared. I think this was whatever was leftover from when I turned it on last night. So how would backwashing the filter relate to this problem if it happens when on recirculate and waste positions? Still scratching me head...

[PoolDoc]

Dirt remains in the filter, until you remove the DE -- and the dirt trapped in it -- by backwashing or by opening the filter can cleaning it manually.

A DE filter works when the waterborne DE powder is trapped on the filter membranes or septum, and remains held their by the water flow, and resulting differential pressure across the membrane, sort of like a sponge stuck to the nozzle of a vacuum cleaner. When the pump is turned off, the DE is released and falls to the bottom of the filter, along with the captured dirt. When the pump is turned back on, the water circulation stirs up the DE -- AND the dirt -- which then swirls around the chamber until the DE is again trapped against the septum.

HOWEVER, until the septum is fully coated with DE, dirt in the water is free to flow THROUGH the septum, since most of the particles are too small to be caught by the fabric of which the septum is constructed.

BOTTOM LINE? It's probably time to manually clean your filter. Wear old clothes and shoes, and plan to take a shower after!

[bjb1966]

Well I think I might be getting some more clues. I have manually washed the filter a few times already so I don't think that is the main issue. As I was vacuuming to waste this morning, I noticed that there was barely any suction. It would come and go. When I turn the system to suck water entirely through the skimmer (which is where the vacuum hose goes in) there is literally no suction. If there is a blockage or issue in the line from skimmer to pump, this could be the air and the dirt going back into pool, etc.

Question: Can you snake a pool pipe or do a camera to see if there is something in the line which is causing any of this? I'm thinking this could be creating a problem with the DE getting to the filter properly when I recharge it.

[PoolDoc]

Usually, you cannot 'snake' pool lines. A drain snake will go through DWV turns, because of the longer radius. But when you use S-40 pressure fittings, you usually can't get the snake past the first 90 degree turn . . . and there's the danger that if you DO get past the turn, you won't be able to retract the snake.

. . . people have had to dig up decks!

[bjb1966]

That makes sense. Two years ago when we were closing the pool my husband accidentally dropped a small plug down the skimmer hole (he thought it was the right one, but it wasn't). There was no way to retrieve it at the time and the pool company we use assured us that the gasket would break down over time and be fine. They also upon opening the following spring tried to blow a lot of air (i think or water) through the line to get it to come through. It never did and we have never seen it. I have a bad feeling this could be causing a problem. Possibly stuff is getting stuck around it and then free from it which is why the suction is intermittent. But we didn't have this problem last year except for that we have never had very good suction from pool skimmer or it is intermittently good.

[PoolDoc]

What kind of plug was it?

Rubber or plastic is unlikely to ever break down, but if it was something else, it might be possible to add chemicals that *would* 'eat' it up.