Leak detection and repair - suggestions?

[aylad]

The info that came with the liner wants total alkalinity at about 100 ppm, and calcium hardness at 100 ppm minimum. I seem to recall reading either on this site or another similar one that calcium is unnecessary for a vinyl pool. Any comments?

Regarding the issue of calcium in vinyl pools--that info was probably just advice the printer was told, rather than based on any good reason....HOWEVER.... In all actuality, it won't hurt for CH to be 100, it's easy to get it there if you're using cal-hypo for chlorination or shocking, and it's possible that there's some form of calcium in the makeup of the liner that you have that would require it to be present in the water. If the warranty ever might become an issue, then I guess it would be better to keep the water levels where they want them, even if there's no solid reasoning behind it!

Janet

[Poconos]

It sounds like you have a partial blockage of the main drain as you said there is some flow. Therefore I suspect compressed air won't do much. It is high pressure, low volume. Something like a shop vac in blow mode with high volume won't have the pressure to blow the water out with that much water depth. However.....how about rigging a fitting to that auxiliary intake to adapt a garden hose and use water to flush backwards? You have the pressure, fair volume, and the mass of the water working against whatever is plugging the line. If you want more volume of water, you can make the fitting adapt to two or three garden hoses to get more flow from multiple sources. PVC is cheap and you can make all kinds of crazy adapters. Let your imagination run wild in the Home Depot plumbing section.
Al

[George in Georgia]

Interesting ideas, Poconos!

BTW, I mentioned the problem to the good folks who installed the new liner, and Buster (no kiddin') speculated that the extra suction inlet might be for a water powered cleaner. I've toyed with the idea of connecting the pool vacuum hose to this inlet to see what might happen. If it is indeed plumbed to the main drain, that suction might move the clog to the skimmer box. I can't see how it could hurt.

[Poconos]

I guess the only danger may be jamming the obstruction tighter. Would be nice if you could suck it out the way it came in.
Al