Inground 18 x 36, vinyl liner (due for replacement - gotta wait), poly lines, 2 returns and unused pool sweep line. Opened this year and after running the pump for 2 hours I had major floating liner (no water loss without the pump running), so I shut it down and capped the deep end line which I thought was leaking. I also called for someone to pressure test the lines for me.
However, after an inch plus of rain the one weekend, the water level had not risen in the pool, so I capped the shallow end return as well and had no water loss for a week. Just for kicks I removed the plug on the shallow end return and it seemed to actually be dry since there was a lot of suction on the plug. Definite leak on that line.
I was still waiting, after more than 2 weeks, for the pressure test, so I decided to try something on my own. I changed the plumbing so what formerly flowed to the shallow end return was now flowing to the pool sweep line. All seemed pretty good for a couple of days, although a slight bulge in the liner around the deep end return. Fast forward to last weekend and the liner has water behind it again, although not nearly as bad as at opening, and water loss, more pronounced with the pump running, approximately half an inch a day.
Now, I'd actually like to dig at this point and fix the leaking returns, but can I get by using only the pool sweep return which I think is OK? Can't really dig if the ground is that saturated anyways. Seems like it should work to me, and add an elbow inside the pool so I get circulation. My alternative would be to add a temporary return over the pool deck to the shallow end. Pump is a 3/4 hp Sta-rite.