I have a kidney shaped pool and a connected 6ft diameter spa (shares water via a spillover that's just below the typical water line). I estimate it to be about 15,000 gallons total being moved by a 1 hp pump. It has one skimmer in the shallow end, close to the steps; 2 return lines, also near the steps; and 6 floor jets spread throughout the pool (as well as the spa jets and drain). The main drain is in the deep end, but is having some problems. Anytime it's open, a little air gets sucked into the pump. I'm not certain that the floor jets are working very well either, especially in the deep end. This obviously gives me some concerns about the circulation of the water in the deep end of the pool.
1) Is there any good way to test how the water at the bottom of the deep end of the pool is circulating?
2) What's a good way to test if the floor jets are working?
3) I'm having the pool resurfaced in about a week and we had talked about filling in the floor jets and plumbing a couple new side returns. What's your opinion about floor jets vs. side returns vs. a possible combination of the 2 (don't fill in the floor jets, but still add the side returns)?
4) Is a 1hp pump and 200 sq ft cartridge enough to properly circulate and filter 15k gallons of water? The equipment is about 15 feet from the main drain and 30 ft from the skimmer.
5) How big a problem is it to have some air sucked in through the main drain? What kind of damage / issues can this cause?
Thanks in advance for any and all help!