Swimming pools blog

Hey all.. I’m a newbie here. My wife and I bought a house with an old
in-ground vinyl pool and I’m trying to learn about it and get it
opened up for the season. It’s 18×36, has a year old liner and a
Nature2 cartridge system, sand filter, and no heat.
The sand filter is old, and has been painted over so I’m not sure what
the make/model of it is, but I suspect it’s from the early 90’s. I
found a filter with similar shape/size and parts in a catalog at the
local pool supply shop. It looks like a Pentair Triton II and has the
lid with pressure gauges on top.
But I’m kind of stuck right now because the seal around the top of the
sand filter leaks even after I tighten the lid down with the big
“filter top” wrench (ocagonal thing with two handles). I’ve noticed
that before it begins to compress the rubber o-ring there is a
considerable amount of play between the lid and the filter tank. The
lid also almost popped out once when I turned the pump back on. It’s

building up about 15psi before it starts to leak. Wather comes out
both of the returns with good flow, etc..
The threads on the sand filter look ok, and the lid screws in fine,
but I’m feeling like it has been cross-threaded at some point over the
years and the threads are bad… or maybe the previous owner put the
wrong lid on the tank.
The previous owner had the pool open summer before last but didn’t
open it last summer. He indicated that it was all functioning ok. I
also noticed that he had a lot of goopy/greasy sealant on the threads
of the filter lid.
Is there a way to repair the threads in the fiberglass filter tank?
Or am I better off buying a new one? I’ve ordered a new o-ring since
the old one was stretched.. but I’m doubtful that will solve it.