Sand Filter & Pump HELP

[jguajardotx]

Hayward 1.5hp Pump
Hayward Sand Filter Model S166T
When I begin filtering I usually backwash for a minute or so and then rinse for about the same amount of time. Usually till the little glass connected to the side of the filter runs clean. When I switch to the filter setting and run the pump everything runs great. The gauge shows about 17psi and the return in the pool is pumping water back in the pool strong. After about 10 minutes or so the return pressure back into the pool gets very weak, but the gauge still has a good psi reading. If I repeat the backwash/rinse it will go back to normal though. I don't think that's the way it works though. Any insight would be appreciated.

 

[jblizzle]

What does the water look like? Does the gauge go to zero with the pump off?

It would take a combination of things for the flow to drop that much but the pressure to stay the same ... actually I am not exactly sure how that can happen as I think about it.

 

[jguajardotx]

Water is murky and had some algae. We took to it today and got most of the gunk out. Yes when the pump is off the gauge does read zero. Pump and filter had been sitting for quite some time.

 

[jblizzle]

Hmmm ... so the pressure stays at 17psi? Is that what you mean by "a good pressure"?

With dirty water I would not be surprised that the flow quickly is reduced as stuff in the water is captured, but that should raise the pressure.

 

[jguajardotx]

Just went out back to double check and yes it is still holding at 17psi (return is weak again). I say that 17psi is "good pressure" only because at the start that's what it reads and returns the water with force. Is that considered good psi? This is our first pool and we really have no clue as to what would be considered a solid psi reading. If the return becomes weak because of stuff being captured would it be alright to allow to the pump to run through the night? Our main concern is allowing the pump and filter a good amount of time to do their job.

 

[jblizzle]

There is no good psi ... every pool is different.

If the flow rate has reduced as much as you say it has already, then the filtering ability has been reduced as well. When you backwash does the water look dirty?

I think I would suggest getting a new gauge just to rule it out. The glycerin ones that tftestkits sells are very nice for a similar price to the junk usually found locally.

 

[jguajardotx]

Yes when I backwash the water is dirty. I guess I'll try looking for a new gauge tomorrow and see what that does.

 

[S1ngram]

I just started up my pool today. My filter pressure went from 16 down to 12. I backwashed and nothing happened, but when I cleaned all the leaves and other stuff out of the skimmer basket, it went back up to 16. Have you looked in your basket yet?

 

[jguajardotx]

Yeah I've been keeping an eye on the basket as well. After backwashing/rinsing all afternoon I'm starting to notice the return flow is lasting longer and longer each time. I'm going to keep skimming and cleaning the pool as much as possible to give the filter as much help as possible. Thanks for the input fellas....

 

[jblizzle]

I am pretty sure the filter is working as it should, but the pressure reading just does not make any sense, which is why you should try a new gauge. The pressure is easier to know when to backwash (20-25% over the clean pressure).