I'm currently planning a new pool build. A couple PBs offered upgrades to use these twirlybyrd jets.
I'm currently thinking 7 ft circle spa with 6 jets. (seems pretty standard)
Anyway they spec 20-30 GPM for best performance. So if I take the most GPM scenario I would need 30*6=180 GPM
Assuming ample sizing of the runs to the jets, say a 2.5" pipe or 3" pipe
Q1: 2.5" return would be 120 GPM at 8in/sec as stated in TFP piping chart I found. I'm assuming if I go over 8in/sec the Head Loss is increasing and thus the max GPM of the pump is going down.
Q2: The PBs both spec'd a 2HP Pentair VS pump, but it seems like I can't really make the 180GPM number with it? perhaps the Pentair IntelliFloXF VS 3HP would do it if I could get the head loss down. I found a curve chart for the pentair pumps on their website that I'm going off.
Q3: Then I looked at the spa drain, just looked up some standard pool drains, looks like you usually do a set of 2 (which seem to have 2" connections) connected to maybe 3 inch piping to the pump. The 3" pipe gets me over 180 GPM at 8in/sec so that seems fine, but the drains are rated at 74GPM per grate, so like 140-150GPM, so does that mean my kid will stick to the drain? Do I actually need 4 drains in my spa?
Q4: One PB said if I add a 2nd pump we can do 8 or 10 or more twirlybyrd jets, makes sense but also makes me wonder back to the Q3, the drain scenario? And also, this is assuming I'm not keeping the water warm and have any heating going on, which could be a different pump etc, lower flow rate, etc, but still the same drain intake?
Thanks for any insights or thoughts, it's been a lot of fun reading the TFP board in my research so far.