Recently bought a house with a pool. From other things we found around the house, it appears that the previous owners were not the greatest at home maintenance. I suspect that this carried over to the pool as well.
Three days ago was the first sunny day we had since getting the pool swim ready (after SLAM'ing, because the prev owner let it turn green). While playing with our snorkeling gear, my daughter and I made a few dives on the main drain. The thoughts that went through my mind were, "Hey! That drain's all clogged up... Hey! my ears hurt!". So my daughter, who wasn't bothered by the ear pain, made a bunch of dives, and cleaned out a lot of gunk. Gunk which wound up all over the surface and bottom of the pool. It took me at least an hour of vacuuming and skimming to get it usable again.
Here is a photo of the drain from the surface:
Notice the rectangular openings. I managed to clear one of those before the ear pain got to me, and the opening became almost the same color as the cover. So I'm guessing that my daughter didn't manage to get all the gunk cleaned out. Not blaming her. It's not easy to clean out stuff at the bottom of an 8 ft pool. Also note that the cover seems to be off center a bit. I don't think that it's screwed down.
Now... what do I do about this? I want ALL the gunk out of our "new" (to us) pool. There are two lines coming from the pool to the pump, and we have one drain and one skimmer. One line has a manual valve. I'm guessing that this goes to the main drain. Is this a reasonable assumption? If so, can I just close off the main drain, move the cover, and use the vacuum to clean out the gunk? Would this damage anything, like, say, the pump?
Any other options?