I am scratching my head on this one. I had a small leak from the bulkhead fitting - not the variflo valve, but from the fitting the valve attaches to. I tried to tighten the bulkhead fitting some more, but the leak increased. I took the fitting out and the o-ring looks brand new. Reinstalled and it still leaked, even more. I backed it off and the leak went away, but when I turned my filter off, there was an air leak at the fitting, which sends my DE back into my pool. So if I tighten it, water streams out, if I loosen it, the leak stops, but air streams in when my filter shuts off.
I am thinking that maybe something wedged the outlet elbow, which the fitting screws into, just a little bit - a clump of dirty DE or something? I am not an expert, but the behaviour seems weird and I can't use my timer as when the filter shuts off, all my DE will flow back into the pool. Its going to be cold and rainy tomorrow and I am going away Thursday, for a couple of days, but any help on what may be the problem is appreciated. Thanks.