New balboa 2000le spa pack upgrade been running 2 weeks with no issues. It replaced a Pro Shield spa pack in a Leisure Bay 21000 tub. . My spa has a 24hr Grundfos pump for my filtration/heating. It it supplied from the discharge of pump #1 ( 1.5hp single speed). When I turn on pump #1, it supplies the jets on 1 side of the tub as well as forcing water through the Grundfos, heater, filter. and discharges through 2 jets in the footwell area. From what I have read on this forum, you do not want the the pump on high the same time as the heater. Depending if the system is calling for heat and I turn pump 1, they could both be on at the same time. Could this cause a problem or shorten heater life? It may be possible that on the old spa pack that there was an interlock to prevent this from occurring, but don't have that info available anymore.

Just because you have water flowing through the heater, that doesn't necessarily mean that your heater automatically comes on. Double check to see if the system is actually heating when you have the main pump on. On hot tubs that I've worked on, however, the inlet for the circulation pump is usually located on the inlet side of the jet pump.

There won't be any decrease in life of the element by having the higher rate of water flow.

I too would think that the circ pump should have been fed from the infeed to pump 1, but it is definately fed from the output of pump 1 and when running there is a big increase in flow through the circ pump circuit and exiting at the 2 jets at the footwell. As for the heater, it is independent of pump 1 (or 2) and comes on as needed, whether pump 1 or 2 is on or not, as long as my circ pump is running and has pressure. It seems to be working the same as before the upgrade, so it'll probably be fine. Thanks for the input.