High Pressure Low Output (with a twist)

nypictaker

New member
Jul 11, 2016
4
Miller Place/New York
I have been reading the forums and see some similar issues but not quite what I am seeing.

The Issue


Turn on system (1 1/2 pump, sand filter, both Hayward) Pressure is at around 15/16, water flow is nice and strong. After about 30-40 minutes pressure starts creeping up and flow gets lower. 90 minutes later pressure over 20, flow almost not existent. Back washings seems to "reset" the cycle.. but same thing happens.

First thing that came to my mind was a suction side air leak... but the the pump basket is completely full.. no bubbles or anything just clear water. I have reconnected all hoses.. nice and tight no leaks there ( i even lit some inssense to see of i could get some smoke to pull to the suction..nothing). When i attempt to vaccum the pool.. i lose all suction with in 5 - 10 minutes.

I am hoping one of you have some suggestions as I am at wits end and the wife is saying to just put the winter cover back on and scratch the season as a loss.




 

borjis

LifeTime Supporter
Aug 19, 2014
3,342
Pacific NW
Have you ever deep cleaned your sand filter?

It might be a ton of junk at the top...possibly. It would be worth taking off the top and checking at the very least.
 

GreatCanadian

LifeTime Supporter
Jul 28, 2011
844
St. John's, Newfoundland
It sounds like it could possibly be the start of an algae bloom. 2 things make me think that. Firstly, you said you have little or no flow after 90 minutes. Secondly, you said that it seems to "reset" itself after a backwash. It sounds to me like the filter is doing its job, but there is lot for it to filter, hence the clogging. Barring an issue with the filter itself, an algae bloom is a strong possibllity. Can you test your chlorine level?

GC
 

nypictaker

New member
Jul 11, 2016
4
Miller Place/New York
It sounds like it could possibly be the start of an algae bloom. 2 things make me think that. Firstly, you said you have little or no flow after 90 minutes. Secondly, you said that it seems to "reset" itself after a backwash. It sounds to me like the filter is doing its job, but there is lot for it to filter, hence the clogging. Barring an issue with the filter itself, an algae bloom is a strong possibllity. Can you test your chlorine level?

GC
Water is crystal clear and chlorine and PH within level.

This is by far very very confusing.
 

crokett

Well-known member
Jul 17, 2007
595
Hillsborough, NC
When the pressure goes up and the flow drops, is the sight glass clear or dirty when you start to backwash? If it's clear, then the problem is not a clogged filter. Have you thought about bypass the filter - not pump to waste but return the water to the pool without it going through the filter? How old is the pump/motor? Is it hot to the touch when the pressure drops?

Took out the part about the broken filter, didn't see your post about new laterals.
 

nypictaker

New member
Jul 11, 2016
4
Miller Place/New York
When the pressure goes up and the flow drops, is the sight glass clear or dirty when you start to backwash? If it's clear, then the problem is not a clogged filter. Have you thought about bypass the filter - not pump to waste but return the water to the pool without it going through the filter? How old is the pump/motor? Is it hot to the touch when the pressure drops?

Took out the part about the broken filter, didn't see your post about new laterals.

When filter is in bypass mode it runs like a champ for hours! Backwash is clear. The pump is warm.. not really hot.
 

crokett

Well-known member
Jul 17, 2007
595
Hillsborough, NC
If it runs ok in bypass mode, then it's got to be something in the filter causing the problem, somehow. Backwash is clear when it happens so the filter isn't getting too dirty. if the motor isn't getting hot, then it's probably not something like a failing motor. At this point I think I'd be taking the filter apart again. If the problem happens and you just turn the pump off w/o backwashing and wait, what happens? does the problem go away, or do you have to backwash to get the flow rate back up? Do you get sand coming out of the return when the problem happens?

Questions I ask my customers

Is this a new or existing setup?
If existing, when did it stop working? What changed?
 

GreatCanadian

LifeTime Supporter
Jul 28, 2011
844
St. John's, Newfoundland
I find it hard to determine clear water from dirty water in my sight glass. Anytime I backwash the water in the sight glass looks clear to me. But I have a small sight glass, so that would make it hard to determine as well.

I asked the OP for a FC measurement but only heard back that it was "in level". I'd like to know his FC level and CYA level, and how he got those measurements. I'm not ruling out algae yet! :) His pool can be visually clear, but still have algae starting. I may be totally wrong, but his filter behavior is precisely what would happen when filter is cleaning an above-normal load.

GC