- Jan 4, 2016
- 5,392
- Pool Size
- 44000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
Don't sweat, a 75 GPM filter will work fine; comments below.
Your biggest single source of head loss is your filter. With the pump right beside the pool and short runs of pipe. Your next main sources might be the return eyeballs creating jets to push the water around. Then there's check valves, diverter valves, all the fittings (90s, 45s, tees, couplers, unions) some resistance going through the skimmer baskets and the chlorinator, etc., and then a bit from the pipe. All the gadgets and direction changes in the system will be about the same whether it's by the house or by the pool. There would be a slight increase in fittings if put by the house, but not a whole lot. I don't want to say you're reading the pump curve wrong, because you're not, but all of these restrictions to water flow mean a loss of 10 or 15 PSI (23 to 35 feet of head) to friction at 75 GPM, so the pump will never push the maximum amount of water that it is capable of.
An extra 100 feet (there and back) of 2" pipe flowing at 75 GPM would add a little below 4 psi (10 feet) of friction loss, but running at low speed (which it will 90% of the time) with flow of perhaps 25 GPM would only add around 0.5 PSI (1.1 feet). Or if you need a bit more for good cleaning, say 35 GPM, the loss is around 1 PSI (2.3 feet). Pint being that most of the time, the friction loss getting to the house is not much of an issue.
It's the friction loss from all these things that total up to the work the pump is doing, which is provided by electricity you pay for. Either way, you're well within normal things that are done with pools. You'll probably only use high for backwashing (not relevant to the circulation system) and mixing chemicals sometimes or doing a fast skim when needed. If the flow is too much for backwashing, you would dial down your maximum speed, or use a lower speed for that purpose.
A bigger filter gets cleaned less often, and (personal opinion) will start filtering fines faster after cleaning. For my money, and your choices, I'd use a 75 GPM filter and save the $500. If the VS pump pushes more than 75 GPM (and I experienced some sort of problem as a result), I'd set high speed on the VS to something less than 3450 RPM.
If choice was open, I'd get expert opinions and buy a decent but perhaps cheaper 28" or 30" filter. If my wife asked me to, I'd take the multiport valve off and paint it almond, though I recognize that factory color is going to look nicer long term. I can't comment on USA brands and stuff, but casey, gwegan and other experts here know their stuff, and can point you in the best direction, if any of those brands are suss. They will also correct me if I've said anything wrong or misleading, one of the great things about TFP. I hope that covers it. If there's something I missed, maybe just post those specific questions.
Your biggest single source of head loss is your filter. With the pump right beside the pool and short runs of pipe. Your next main sources might be the return eyeballs creating jets to push the water around. Then there's check valves, diverter valves, all the fittings (90s, 45s, tees, couplers, unions) some resistance going through the skimmer baskets and the chlorinator, etc., and then a bit from the pipe. All the gadgets and direction changes in the system will be about the same whether it's by the house or by the pool. There would be a slight increase in fittings if put by the house, but not a whole lot. I don't want to say you're reading the pump curve wrong, because you're not, but all of these restrictions to water flow mean a loss of 10 or 15 PSI (23 to 35 feet of head) to friction at 75 GPM, so the pump will never push the maximum amount of water that it is capable of.
An extra 100 feet (there and back) of 2" pipe flowing at 75 GPM would add a little below 4 psi (10 feet) of friction loss, but running at low speed (which it will 90% of the time) with flow of perhaps 25 GPM would only add around 0.5 PSI (1.1 feet). Or if you need a bit more for good cleaning, say 35 GPM, the loss is around 1 PSI (2.3 feet). Pint being that most of the time, the friction loss getting to the house is not much of an issue.
It's the friction loss from all these things that total up to the work the pump is doing, which is provided by electricity you pay for. Either way, you're well within normal things that are done with pools. You'll probably only use high for backwashing (not relevant to the circulation system) and mixing chemicals sometimes or doing a fast skim when needed. If the flow is too much for backwashing, you would dial down your maximum speed, or use a lower speed for that purpose.
A bigger filter gets cleaned less often, and (personal opinion) will start filtering fines faster after cleaning. For my money, and your choices, I'd use a 75 GPM filter and save the $500. If the VS pump pushes more than 75 GPM (and I experienced some sort of problem as a result), I'd set high speed on the VS to something less than 3450 RPM.
If choice was open, I'd get expert opinions and buy a decent but perhaps cheaper 28" or 30" filter. If my wife asked me to, I'd take the multiport valve off and paint it almond, though I recognize that factory color is going to look nicer long term. I can't comment on USA brands and stuff, but casey, gwegan and other experts here know their stuff, and can point you in the best direction, if any of those brands are suss. They will also correct me if I've said anything wrong or misleading, one of the great things about TFP. I hope that covers it. If there's something I missed, maybe just post those specific questions.
it will get done one day
when they get moving get out of the way! WOW!