wlow60,
Which model heater do you have and how many gallons is your pool. Based on your post, sounds like you have not isolated the spa for the heater and are heating both pool and spa which will take a long time (and use quite a lot of $).
To isolate the spa for the heater you need to move the valves on the pipes going into the front of the pump so the pump is sucking water in from the spa and not from the pool.
Then you need to move the valves that are after your filter so the water goes back to the spa only and not into the pool.
If you did this correctly, with the pump running the spa water level should not change. If the spa level is dropping then you still have water going back into the pool. If the spa level is rising, then you are sucking water from the pool and not the spa only.
If you could post pictures of your pool equipment and valves we can help identify what you need to do.
I have a medium size spa ( 6 people) and it only takes about 30 mins to go from 86 deg to 102 deg.
Some heaters have separate temp controls for spa or pool so you may want to check your heater settings as well to make sure you are heating in "spa" mode.
If you didn't know, you need to keep pump running the whole time the heater is on and leave the pump running for at least 5-10 mins after you shut heater off to allow manifolds and piping inside the heater to cool off gradually.
