I am renovating a 16x32 in ground pool 5' deep in the center about 17,000. Outside Chicago area. The pool has a main drain & skimmer and two returns. It had an 30 year old Hayward sand filter rated at 2.5 sq ft filter area and 50 GPM max pressure 50 psi and a Hayward 3/4 hp super pump. All fittings and piping are 1.5". I want to move from the sand filter to cartridge. I was looking at the Hayward star-clear plus line. I was told I should get a larger filter and was looking at the the C751 (cause the flow rate was a little larger than the current sand filter and still used 1.5" piping. A pool builder I was talking to said I could go much higher up to a 120 GPM filter. He also said that I should add a more returns and increase the return piping to 2" while keeping the suction at 1.5". I can get the 75 gpm, the 90 gpm, and the 120 gpm in wither 1.5 or 2" fittings. Never had any issue with the 1.5" piping, that I was aware of. Hayward says in their documents that 90 gmp and above should use 2" pipping. Would it help to add a 3rd return or go to 2" piping without adding a 3rd return? Is it OK to have 1.5" suction and 2" return? I have put a basic diagram of my pool and the old and new filter with potential 2" piping and a 3rd return. I hope it makes sense. Any and all suggestions would be greatly appreciated.
pipe sizing and filter for pool renovation
- Thread starter DavidJohnson
- Start date
- Jul 21, 2013
- 66,450
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
First of all your 3/4 HP pump cannot push more then around 70 GPM through your system. So those higher flow rates are meaningless for you.
The reason to get the largest cartridge filter you can is you need to clean it less often.
If your 1.5” return pipes are fine there will be no visible benefit if you change them to 2”.
You can use 2” pipe on your equipment pad if you want.
I would rather add another skimmer to your one skimmer then add a third return. I doubt a third return will make any visible difference. While a second skimmer will improve your water skimming.
The reason to get the largest cartridge filter you can is you need to clean it less often.
If your 1.5” return pipes are fine there will be no visible benefit if you change them to 2”.
You can use 2” pipe on your equipment pad if you want.
I would rather add another skimmer to your one skimmer then add a third return. I doubt a third return will make any visible difference. While a second skimmer will improve your water skimming.
Flying Tivo
TFP Guide
- Jan 24, 2017
- 3,100
- Pool Size
- 7500
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Flow rates on filters are the manufacturer's recommended maximum flow rate that seldom are rooted in reality. For pool purposes, pipe of 1.5" the maximum should be about 50 gpm. That "recommended" filter is a dinky 75 sq. ft. clean-me way too often, buy new cartridge regularly filter. For longevity and no buyer's remorse, get a filter at least 300 sq. ft. Cartridges themselves can handle about 1gpm per sq. ft. but the limiting factor will always be the plumbing. It is a misleading way of selling a filter. Be more concerned about how much dirt it can hold before needing to be cleaned.