Hello, Laura here , I am a recent widow and have the task of closing my inground cement kidney shapped pool the was built in the 90's I have a question, there are 2 drains on the bottom 18.500 gal kidney shaped pol no jet or return lines,i kind of remebered  he would blow lines from skimmer box plug and i would get 2 bubbels under tarp, I only got one. The drain in shallow part, is this a poblem?, When pool was open the 2nd drain  at shallow end was aliitle behind when  filter was on  to makie bubbles  Help PLEASE!!!!  - lstili@yahoo.com