I'm looking for some help with a problem I'm having. FYI, we did not install the pool. We bought our house last year and it was already here. I'm learning on the fly.
The pool has been opened for a week. Ever since then, I noticed DE has been returning to the pool. After doing a search, I saw that one common reason was a hole in the filter screens. I took apart the filter and noticed that one of the screens had a hole in it. I ordered a new screen and installed it yesterday. I also added six pounds of DE to the skimmer baskets.
I checked the pool today and the entire pool floor is covered in DE, when previously it was a light coating on the stairs by one of the returns. Before I go and replace all of the filter screens, are there any other possible reasons for this happening?
Secondly, I used the pool broom to push the DE towards the main drain but it looks like the main drain is not working. When I close the valves to the two pool skimmers, the filter pressure drops to zero. My assumption is this should not happen if the main drain is working.
Here are two pictures of my plumbing: http://imgur.com/Jd0SeeB and http://imgur.com/FfFVa
From left to right the valves are labeled: pool main drain, waterfall, spa main drain, spa skimmer, pool skimmer #1, and pool skimmer #2. To further confuse the issue, the pump on the far left, which appears to be hooked up to both the pool main drain and the waterfall, only turns on when the waterfall is on (one hour a day). Could it be set up such that the main drain only works when the waterfall is on?
Any help would be greatly appreciated.