Problem started upon opening of pool. 20% is all I am getting out of the total flow coming from the main drain ball valve going into the basket in front of pump. Turned off skimmer ball valve and not enough water comes from main drain ball valve to sustain pump. Skimmer ball valve works with enough water to sustain pump. Used the skimmer drain and vacuum all season to circulate water, chemical levels did fine, pool did not drain, water level went down due to evaporation.
Both valves worked in 2013. Did change ball valves in 2013 as handle came off old ball valves couldn't work the valves.
Time to close pool and I am concerned with line coming from main drain freezing.
There is a butterfly valve buried 2 feet in ground, I believe comes up from the main drain; turned that each way watching nothing changed.
Pool was built in 1994, I have no plan of pipe layout and the company who built it couldn't help me as it was to long ago and the other person who knew past away this January.
Recommendations from local pool supply companies of pressurizing the line with a compressor going into the basket in front of pump and closing skimmer valve and seeing what happens sound risky to me, maybe could explode the pipe.
Surly there is a method to rule out which valve or what other situation it could be with out changing the two related valves.
The very least, a sure method to blow out lines and be worry free from them cracking this winter.
Thanks to all you who have experienced this situation and survived to tell it.