I've been having a lot of trouble - first the pool turned cloudy - got that mostly corrected by cleaning the filter, reducing the flow though the filter, and adding sand. Now two more problems have cropped up. First I'm getting sand fines in the pool. Not a lot, but patches start showing up after about 12 hours after vacuuming to waste. I've back washed the the filter for extended periods. rinsed for extended periods and still the fines collect on the bottom. I assume that means a problem with one or more laterals. Could anything else be the cause? Can anything be done besides emptying the filter and pulling the internals?
Second air is getting in the system from the main drain suction line. I normally operate the filter with the skimmer and main drain lines open and started noticing the pump strainer basket was getting air trapped in the top. If I close the skimmer line I can see air bubbles coming from the main drain line. If I close the main drain and open the skimmer line the bubbles stop. I can't think of anything except a leak or crack in the line that would result in air getting into the system. Any other ideas?
Now the $64,000 question. Can the line be repaired by any means other than digging it up and either patching the leak or replacing the line?