Since the pool was new ( 1 year ago) I have had a very slow leak confirmed with a drop in the salt ppm and the CYA over time. Based on the salt loss I calculated a loss of ~20 gallons per day. We drained the pool this past week and pressure tested the piping to 30 psi using water - no leaks. The fiberglass shell shows no apparent issues. Our soil in this area is decomposed granite and thus water seeps away rapidly so no visible signs of water near or around the pool area.
We have no overflow but do have an auto-fill (we are in the desert). There is no line to waste, we use a submersible pump to drain the pool. No issues with floating the pool here - again we are in the desert!
So now I am at a loss! Are there any areas I am missing? We tested the spa system separately from the pool system.
Thank you in advance.