About 6 years ago we replaced our wood-framed in-ground pool with a
steel framed vinyl-lined pool. Last summer we had a small tear in the
liner (about an inch long), and the pool was losing about two inches
of water per day. We patched it and everything seemed fine - no
measurable water loss, etc.
In October we covered the pool with a mesh spring-loaded cover (the
ones they show the elephant standing on). Just yesterday, about a
week after a 6" snow fall (first major snow of the year), I realized
that because of the weight of the snow, the cover had sagged about 2'
down in the middle. I shoveled the snow off, removed the cover, and
there is only about 10" of water the shallow end (about 5" of ice, 5"
of water). There is no obvious damage to the pool (coping/decking is
all straight, sides don't appear bowed or bent, etc.)
I'm assuming that we have a very slow leak, since it hasn't been that
cold this winter (it's unlikely that a major leak happened just before
the pool froze).
Any advice on whether I should refill the pool so that the freeze line
is higher up on the wall, or does it matter at this point? Obviously
the leak isn't getting fixed until the spring, and I would expect that
the pool will remain frozen for at least the next month or so.