I think something might be amiss. But, I'm not sure, thus the Title.
My skimmer has 2 pipes going out the bottom. There is one of those diverter-plate thingy's (don't you just love thingy's?) and the swing piece is open.
It always has been.
I have never vacuumed the pool in 10 years - screened in and rely on a Polaris and hand brushing. Wouldn't know how to (vacuum).
(But I can rebuild a Polaris blind-folded).
There is obvious suction back to the filter through one of the pipes, the other, I would guess, goes to the drain? Used for vacuuming? Nothing is happening there that I can see.
I have a DE with Multiport valve.
A few weeks back, while I was replacing my Amerilite fixture (that was fun!) I took time in my scuba gear to really inspect the pool. At the main drain - it's full of sand. There is nothing visible in the drain (@ 8' below water level) but...sand down about 2" from the grate. From the deteriorating marcite. Re-finishing is on the schedule for next fall/winter.
My question is - what is the other pipe for and, how to get the sand out of the drain (or do I need to)?
Reason I bring this up - SLAM in May, pool's been perfect - maintain pH @ 7.5, FC @ 5 with CYA @ 30. But. I'm noticing a bit of green in the backwash last weekend, so fine-tuned pH and SLAM the pool tonight.
Run pump 8 hours/day; Polaris 4 hours/day. New spider gasket, new multiport valve top.
Did I not get all the algae out on the first slam? Gunk off the screens from 2 recent down pours (2"+ each)? Not getting the "right" circulation because of the main drain?
Not up on how the plumbing should work, that's why posted here. Moderator, please move if in the wrong place.