so in the beginning of the season y'all helped me get my variable speed pump situated.
*i disabled the main drains, drawing strictly from the skimmers.
*i have a high speed setting that runs for 2 hours, strongly generating a circular flow of water around the perimeter of the pool
*i have one low speed setting strictly for generating chlorine via salt water generator, that runs slow as possible, yet fast enough not to run the pump dry.
the pump has run dry on three occasions, i was there for both of them miraculously.
1) when the pool people serviced the pool, they somehow closed a weir valve in the skimmer, halving the water flow into the pump.
2) when that same weir valve mysteriously shut itself again from yesterday to today.
3) when the junky vacuum hose they provided me fell off of the vacuum head. i had to jump into the pool with my clothes on to keep it submerged. (it was a 60' sprint to the pump).
my concerns are as follows:
1) why is that weir valve shutting itself? i put a washer between the screw that attaches the weir valve to the skimmer unit so that i can thread the screw down tight enough to keep the valve in place. i don't know the composition of the washer, so i'm going to wait for y'all to tell me what type of metal is safe, i'll go buy that type of washer, and replace them.
2) i can't get good low speed flow to the pump with the main drains open; it seems that the pump can't draw any water when it has to fight gravity. this is a concern because when the water level get too low (and we're talking an inch between too low and too high) the pump sucks air in with the water when pulling solely from the skimmers. and it seems to draw from the skimmers much more so than the main drains to the point where if water level is on the low side, i can't use the skimmers for suction whatsoever.
what do i do to prevent this? and if it can't be prevented, how do i atleast make sure the pump doresn't run dry? i'm worried it's going to happen when i'm not there to deal with it.