Attempting to close this myself after my first year of pool ownership.
The returns have been blown with a compressor and I hear a small gargle after shutting the pressure off. This tells me that there may be a little left.
Should I just pour RV antifreeze down the two returns?
I have made pipes with 90 degree elbows that are screwed into the returns then capped. This means I can leave the water a little higher as I have an auto cover...
Any suggestions on that last bit left in the pipe?