Retrofitting Older Hot Tub

[Lebeter]

I purchased a foreclosed home which had a hot tub installed with a pack that looks like it dated back to late 80's/early 90's. Brett something was the name on the control pack. Anyway the 240v lines coming from the house were burned in the control box and it was pretty rusted out. The timer sounded like it was still working but nothing else. So I removed the heater/control box/blower motor out and decided to hunt down a new digital pack after it seemed that the hot tub was actually holding water and not leaking beyond the filter housing slightly. I craigslisted a Dimension One Heater/Ozone pack with topside only to find it needed a recirculator pump. The old setup used a 120v two speed pump that looks like it had been replaced in the tub within the last 8 years. I could not find any diagrams that showed how a hot tub with a recirculating pump should be plumbed into a system that used a two speed pump as the heater circulating pump. Obviously I would have bypassed the heater with the two speed jet pump, but I wasn't sure where to tap into the bottom feed line (inlet) to feed the recirculation pump or if it needed its own feed line from the top of the tub. The only direction I could find was to return the line after the heater into a low spot in the tub. I'm guessing these smaller Laing recirculating pumps are more efficient than running a large two speed pump on low in many systems. Can someone confirm that?

I ended up picking up a Balboa pack used on CL as well that came with a similar pump, only difference was the discharge location on the impeller. Figured I would use this as a backup pump. This heater pack I could integrate into the plumbing easier as this is how the original was designed. I'm going to try and fire this one off tonight, but I'm curious how much more energy efficient the D1 Pack would be with the recirculating pump. I'm only planning to keep the Hot Tub set around 80-85 and use maybe 3-4 times a week. Would it be worthwhile to get the D1 Pack plumbed later? Just curious if anyone had done back to back comparisons of the two designs and calculated monthly savings between them.