Please bare with me in new to pools.
I have an in ground, vinyl lined pool and this spring I was losing water enough that I'd have to top it up everyday. (Run water for half hour maybe more) I had someone test it and said he couldn't find anything. Then I noticed water always under my chrlorinator. A fitting was leaking so I fixed it. Don't know if it was enough to be responsible for a loss like that but around this time it got better. Topping it off only about on e a week.
A week or so ago it started happening again after I vaccuumed the pool. So I have had a chance to test if it's with pump on or off yet. But here's the part that confuses me. I have a small well beside my pool that my neighbour says I should pumpp every month or two. It's been a while and I thougt maybe in some crazy way it can effect my water loss. So I pumped it for about 2-3 hours yesterday afternoon. At this point the pool was topped off in the morning. By the end of pumping it needed water again. So filled it, went to sleep. This morning it's low.