Aqualink RS4 Aux connections

[HermanTX]

Yes, there was some confusion on my part. I was under the impression that I need Spillover mode. With my flush spa, it might not be needed. There's a Spa makeup (I believe that is term) that is active in Pool mode. This returns some water to Spa. Also, it does move some over the wall (back and forth).

I tested with the heat pump last weekend and I can maintain 102. It does take about an hour plus to get to that temp, but I think that is normal for a heat pump (gas heater took about 10-15 minutes). As you sit next to the pool, you can feel cooler water.

Great. You can still discuss with your PB but think you are right track.
The spa makeup keeps your spa chlorinated and pushes water over to pool. I have the same thing however, I cannot turn mine off. It is a permanent line to my spa which is active when in Pool Mode. Check to see if you have a valve to control the spa make up however with a flush spa it probably does not make much difference.
If the spa can hold heat then it appears to work well. Yes, a gas heater would be quicker as you noted.
Enjoy the pool & spa.