Hi Plsbcheap:
Glad to see your project is coming along and your making some progress with thinking.
UNFORTUNATELY of late, it seems most of the posters with technical know-how on this forum seem to be spending their time on less meaningful subjects, but I guess everyone needs a break now and again. :-/
I really like the combo pool and spa approach, although I need to tell you that most people I know who have one live in warmer climes with year-round pools. Efficiency is an issue, even with careful preparation.
If I was doing your project, I'd think about the following. First, if I was going to combine pool and spa filtration, I'd get a high-end, high-volume cartridge filter. The Jandy
CL 460 or CL 580 looks like a good choice. Note the high filtration capacity and a work rating of 180 to 225 GPM for both these filters. Needless to say, you need a bigger filter to handle both water sources and, REMEMBER, spas need MORE filtration than pools, especially for suspended organics. A size up for filtration would be my choice, just so I'm NOT doing filter cleaning every week. You also need a higher GPM filter if you are planning to use your pool pump as a spa jet pump on "high speed" setting. Your contractor will have a recommendation for this if he has decent experience with shared circuit systems.
I'd also consider using a higher end digitally controlled heater, sized for the pool. Don't worry about it being right for the spa, as long as it's natural gas and has two-setting and switching capacity it should be fine. Sticking with Jandy, the
LX model heater looks like a good choice. Unlike "normal" spas, your spa will remain cooler (maybe pool water temp) until you want to use it. When you get ready to use it, you switch circuits and that big pool heater brings your spa to temp in less than 30 minutes.
Now, I'll bet that "waterfall effect" comes from circulating the spa WITH the pool. What I mean by this is that when the spa is "off," the pool filtration circuit opens to the spa, causing it to "overfill." Because of the "waterfall," the spa water spills into the pool causing it to return through the pool suction. When the spa is turned "on," the pool filtration cycle cuts out, keeping the spa water in the spa and allowing it to heat.
Ok, so how do we put it together? Here's what I'm thinking. To start with, the pool circuit is suctioned from the pool, filtered, heated, retuned to the spa and then spills over into the pool. The spa remains at pool temperature until used. When the spa is turned on, actuators switch to a circuit suctioned from the spa, filtered, heated and returned to the spa. If the pool pump has "low" and "high" settings, it's used on "low" for pool circulation and switches to "high" for spa jets. If you want more spa "action," plumb an additional high speed pump on an independent circuit that only turns on when the spa is activated. This additional circuit would NOT be filtered or heated. Valve actuators and electronic controls do all the work. Just remember, the "winter" setting for this system needs to cut out pool circulation but still allow the spa to operate. This means draining the above ground pool plumbing, valves, etc. This approach should result in a shared pool pump, filter and heater and is probably what you’re looking for.
Just remember, I'm NOT a pool/spa contractor, but I DID stay at a Holiday Inn Express last night....
Good luck and hope this helps....
Drewski
