First year with the pool. Not sure this is a problem or not... The VSP is putting out about 40gpm based on my flow meter and the filter is registering like 1-2 psi of pressure. I have 3/4 inch return fittings in the pool. Is the low PSI an issue? Should I reduce the return fittings to 1/2 in an effort to produce more back pressure? The Pool looks very clear and clean so not sure there is an issue but the low back pressure seems lower than normal.
Low Back Pressure
- Thread starter ctasche
- Start date
That is fine. You have a 325sq ft filter. the larger the sq ft then the pressure drop across the filter media will be lower. Your pump RPM/GPM also has the same effect, the lower the speed then less drag through the filter media.
Just remember to monitor your filter pressure at the same RPM/GPM setting. Once the pressure rises 25% above the base line then it is time to clean the filter. You would benefit by having a pressure gauge that reads from 0-30 psi rather than 0-60 psi which is what standard pressure gauge on filters.
Just remember to monitor your filter pressure at the same RPM/GPM setting. Once the pressure rises 25% above the base line then it is time to clean the filter. You would benefit by having a pressure gauge that reads from 0-30 psi rather than 0-60 psi which is what standard pressure gauge on filters.
- May 3, 2007
- 17,392
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Not a problem if the pump RPM is low as well.
What is the pump RPM when at 40 GPM?
What is the filter pressure when the pump is running at full speed (3450 RPM)? Flow Rate at full speed?
What is very often confusing in the "more is better" thinking in many things, just the opposite is true in pools with regard to pressure. In the case of pool circulation, a higher pressure reading on the filter gauge means a lower waterflow rate. Its a measure of how hard it is to shove water through the filter media and then the rest of the system after the filter. In reality, pressure (head/restriction) is the enemy of flow.
To get an idea of how this works, on a warm day when your garden hose is softer, fill a bucket with nothing on the hose at full flow. Then, do the same thing with a nozzle, or your finger over the outlet, where you can get the water to spray harder and watch how long it takes to fill the same bucket and how much the hose expands (pressure). You get increased internal pressure, but reduced flow.
Last edited:
IUsedToSail
Bronze Supporter
I've been pondering this same question. I have not yet installed the return fittings and have noticed that I am not getting any bubble at all in the pump, even with it running super slow around 900rpm. It is currently programmed to cycle to 2800rpm for a few minutes every 5 hours. The only downside I can think of is the pool probably isn't getting quite as good dispersion of the water.