After a successful 1st season using the TFP advice and system, we noticed we were filling the pool a bit more than we were at the beginning of the season. I closed the pool and after turning the pump off for the season (we ran the pump 24/7 during the summer), I found the pool level dropped very quickly - lost 3-5 inches within days, and dropped down to below the bottom step by the end of winter. So I reopened pool - hubby cleaned out and regrouted steps where we thought there might be a leak, refilled & started the pool back up. It's sparkly and clean, but still losing water. I've observed that when I am running the pump, the pool leaks little or not at all, but when the pump is off like it was last night - the water drops fast - at least an inch since last night. So where to start?