I have a combination pool/spa setup on my main pump with a Jandy Actuator on the drain (inake) side of the pump. Here is a picture to get an idea of the setup.
Now I have a suspicious feeling that the diverter inside the 3way valve under the JVA is leaking. Because when the pump for the main pool side is running (pool mode where it only draws from the main drain and skimmers of the pool) for say 6hrs, I notice the spa level drop about maybe 1-2". So I opened up that 3way and looked at the Diverter, the rubber part had a crack in it. So I thought for now to see if Im right let me swap it with another one, so I decided to swap it with my 3way valve thats on the Jandy LX400 heater bypass. That diverter looked good to me. So then next day still same thing. I marked the level in the pool and noticed it went up about 1/16" so I know its sucking water from the spa at a very small rate. I couldnt find any part number or 3way number on the valve body itself so I cant seem to be sure what diverter kit (replacement) to get. Has anyone experienced this where you have to replace the diverter inside? They seem to sell 2-3 different types of replacements and not sure which one goes with this one. This pool is about 6yrs old.
I also have the same issue with the check valve for my spa and spa spillover basin, When everything is off, I notice the level in the spa drops about 3" into the spillover basin. So the check valve flapper is bad. Opened that and the seal looks torn and bad.
The right side of this picture shows the spa spillover pump and the check valve at the top.