VS Pump Gradually Loses Flow Until Restarted

[turnstiled]

Hello TFP. Has anyone here run into this kind of issue, or have heard anything about it from elsewhere?

water flow slows down after awhile through pump

I appear to have a Dynamo 2HP pump with a Sand-dollar sand filter. I do not have a timer yet. After a couple of hours or so, the water flow is noticeably less coming out of the return. Also, from looking in the skimmer there is less 'suction'. The skimmer basket is not full, nowhere near...

www.troublefreepool.com

So far it's the only thread anywhere on the web I've seen that matches the issue I'm currently having, but a solution was never found and the thread fizzled. Hopefully someone has anything to share. Thank you!

David

 

[ajw22]

You probably have algae accumulating in your filter blocking the flow.

Tell us what specific equipment you have in your pool.

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www.troublefreepool.com

 

[turnstiled]

Hi @ajw22 and thank you for the reply! No time right now to make a signature, but will list the equipment as best I know it. Also, I use a pool tech as I know nothing of how this stuff works, but we're stumped on the cause and looking for any info we can. The tech even spent an hour with a Jandy tech and the rep was also stumped.

Jandy Breaker Box
Jandy ePump (settings 1750RPM or 3000RPM)
Jandy Breaker extension box for chlorination
AquaPure
Jandy Aqualink RS
Jandy/Hayward Cartridge Filter
Jandy/Hayward Pool/Spa Heater
Spa and Spillover
15k Gallon In-Ground Pool

That's all I have off the top of my head. Sorry I don't have model numbers right now (at work atm).

 

[ajw22]

In our experience you are barking up the wrong tree looking at the pump. The only thing to check in the pump is that the impeller is clear and not clogged.

When was the last time your cartridge filter was cleaned?

What is the clean filter PSI?

What is the current filter PSI?

We suggest you do a Overnight Chlorine Loss Test using your own test kit and see if your pool is algae free.

What is TFPC?

We believe any pool owner can achieve and maintain safe, crystal clear pool water, by using the science-based, Trouble Free Pool Care (TFPC) methodology.

www.troublefreepool.com

 

[turnstiled]

Good to know about the pump (it's brand new and worked fine until recently). So now with algae and the filter being mentioned, I should include that we did a noPhos treatment to get phosphates down from 1700+ a week ago. The filters were cleaned after that and phosphates reduced to 525, but we just did the second noPhos pass to hit zero phosphates so fingers crossed that another filter cleaning will fix the problem. I don't have PSI numbers right now but will find out when my pool technician comes over later today (he checks pressure constantly but has yet to see problems). Thank you so much for trying to help!

 

[turnstiled]

@ajw22 If it was algae in the filter, wouldn't that mean the pump would always be at the low flow, rather than slowly trickling down? Moreover, once the flow has dropped, simply restarting it restores proper functionality (until flow is once again lost over time).

 

[ChrisL]

I recently lost both flow and pressure at the same time. The issue was pine needles blocking the impeller. If the pressure is up, the issue is probably a clogged/full filter from algae or something else. This could be gradual as stuff in the water starts accumulating on the filter media. Even when you turn the filter off, the gunk sometimes suspends in the water and takes a little while to affect the filter again. You will see this in a rise in pressure as the flow goes down. If the flow is down and the pressure is down, check for a problem with the impeller or some other obstruction on the suction side. Make sure the power is off before you reach fingers or anything else into the impeller.

 

[ajw22]

@ajw22 If it was algae in the filter, wouldn't that mean the pump would always be at the low flow, rather than slowly trickling down? Moreover, once the flow has dropped, simply restarting it restores proper functionality (until flow is once again lost over time).

The residuals from your noPhos treatment could be acting like algae and clogging your filter.

If you always maintain the proper FC to CYA ratio then phosphates in your water don't matter and we see no reason to spend time and money to treat a non existent problem. And I think you may be seeing the negative side effects of doing an unnecessary process. We look for the simpilist trouble free pool care process that pool owners can follow.

Read what we think of Phospahte removers here - Phosphate Removers - Further Reading

Over time the water flows through your filter will paint it with algae and hold the algae against the cartridge blocking teh water flow. As more algae blocks the filter the flow reduces.

When you turn off the pump the water flow stops in the filter and the algae and water slump down to the bottom of the filter. This clears up at least part of the filter so when you turn on the pump you get decent flow again. Until the algae accumulates on the filter and the cycle repeats.