I have a Hayward DE ProGrid 24 sq ft filter and a 1.5 HP pump for a 18,500 gal above ground pool plumbed with 1.5” pvc. I have a Blue Wave NE6171B Maxi 1.5hp pump meant for above ground pools bought in fall of 2020. I use 4-5 of the Leslie’s blue scoops of DE when I charge the filter. I just replaced all the grids because I was only getting about two pounds of back pressure before the flow rate fell to a trickle. 10 psi with no DE, 11 psi fresh loaded, about 13 psi and the flow rate has dropped by about 3/4. I haven’t done maintenance on the pump since I installed it. I also haven’t replaced the gasket in the Hayward multi-port since 2020 either. To me it seems the pump is failing to produce decent pressure under load. Is there anything I can look at/ replace in the pump mechanism? Or do I just have a cheap pump and need to shell out $$$ for name brand?
Help with DE filter - Low back pressure, low flow
- Thread starter ChuckB2023
- Start date
- Jul 21, 2013
- 52,817
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Welcome to TFP.
A pool pump either moves water or it does not.
More likely you have algae that clogs your filter and slows your flow.
Do a Overnight Chlorine Loss Test
www.troublefreepool.com
www.troublefreepool.com
A pool pump either moves water or it does not.
More likely you have algae that clogs your filter and slows your flow.
Do a Overnight Chlorine Loss Test
Pool Care Basics Archives
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Swimming Pool Algae: Basics and Prevention
The best offense is a good defense: prevent algae in your pool with chlorine, and avoid expensive algaecides and shock! No more green pools!
www.troublefreepool.com
Well I do have algae. I've been shocking it for several days. After the third time it finally turned blue cloudy. So I'm filtering it out. My concern is that I only get about 2 PSI above the "clean" level before my flow dies off. I keep reading that you need to backwash when it gets 10 PSI above the initial level. But in the 20 years I've had this DE filter I've never been able to get more than about 5 PSI before the flow is so slow that there's no way it can turn over the pool. A few years back I went from a 24' to a 28' and kept the same 24 sq ft DE filter and put in a new 1.5 HP pump. When the pool is clean things are fine, but when I do have to deal with algae the flow just dies after 2 PSI. Just feeling frustrated. Reading up on the max flow rate for a 24 sq ft DE filter (ProGrid) versus the max flow rate of the pump I'm wondering if I'm just trying to push too much water through it. I did a de-grease and acid bath for the grids two weeks ago and noticed that the ribs inside the grids were broken all the way around. So I was wondering if the pressure was too much and it was breaking them off, but as I cleaned them a few more snapped so I think they were just getting brittle. So I bought a new set of grids, loaded it all up, but still only get 2 PSI difference before the flow drops. So now I'm questioning the whole setup - do I need to size up the filter to allow for a greater flow rate? Upside from 1.5" to 2" pipes? Get a 2 hp pump? Look at just replacing the pump impeller? Or is getting a 10 PSI difference between backflushes just not possible with a 120V pump versus a 240V setup? Don't have to answer, just ranting. Off to Leslie's to buy yet another bag of DE and keep on backwashing every 24 hours. : /Welcome to TFP.
A pool pump either moves water or it does not.
More likely you have algae that clogs your filter and slows your flow.
Do a Overnight Chlorine Loss Test
Pool Care Basics Archives
Your one-stop shop for all things TFP to include: ABCs of Water Chemistry, Recommended Chemicals/Levels, Test Kits, Troubleshooting, and much more!
Swimming Pool Algae: Basics and Prevention
The best offense is a good defense: prevent algae in your pool with chlorine, and avoid expensive algaecides and shock! No more green pools!
- Jul 21, 2013
- 52,817
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
You didn’t read about backwashing after a 10PSI rise here. Our guideline is backwash after a 25% rise from the clean filter pressure.
What is your clean filter PSI?
The larger the filter the more algae it can handle before it needs backwashing. You can’t have too large a filter.
A DE filter does great filtering but the downside is when you get a big algae problem it rapidly does it job and needs backwashing.
Your pump nor your pipes are your problem. I would replace your 20 year old filter with a 60sq ft DE filter or a 500+ sq ft cartridge filter.
But with a big algae problem any filter is going to require attention to clear the algae.
What is your clean filter PSI?
The larger the filter the more algae it can handle before it needs backwashing. You can’t have too large a filter.
A DE filter does great filtering but the downside is when you get a big algae problem it rapidly does it job and needs backwashing.
Your pump nor your pipes are your problem. I would replace your 20 year old filter with a 60sq ft DE filter or a 500+ sq ft cartridge filter.
But with a big algae problem any filter is going to require attention to clear the algae.
You have a pool at the top end of the average backyard pool's capacity. Above ground pumps will, in fact, use the horsepower stated on the motor, but won't do the work, they're just energy hogs that eat power and give nothing back. They are "low head" pump at best. That means when it gets hard to push water, they won't. Get your filter a little dirty and the flow drops very quickly.
You need a better pump for starters, one designed for an in-ground pool. For a pool that size, your best option would be a VSP. Run it at a higher speed for a short while to skim and then at a low speed for a very long time for great water.
Unfortunately there are very few that run on 120V. Waterway markets this as an above ground VSP, but it is a Waterway 3/4hp Champion with a variable speed motor ( I recognize the wet end as I probably installed 50 of the single speed pumps). It will run on 240V or 120V. It is also the only VSP that supports both voltages in that price range in a name-brand pump.
Waterway Power Defender 140 Dual Voltage Variable Speed Above Ground Pool Pump 1.40HP 115/230V | PD-140ABG
Pool Supply Unlimited has some of the best prices when shopping for Waterway Power Defender 140 Dual Voltage Variable Speed Above Ground Pool Pump 1.40HP 115/230V | PD-140ABG
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If you don't want to get the VSP, look at this pump, its the same as the above with a single-speed motor (the VSP will pay for itself in energy savings, so it is the better choice).
Waterway Power Defender 110 Inground Pool Pump | 1.1HP | PD-110
Pool Supply Unlimited has some of the best prices when shopping for Waterway Power Defender 110 Inground Pool Pump | 1.1HP | PD-110
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So the 25% rule is what I'm seeing. Clean is 10psi, near no-flow is 12psi. The 10psi thing came right out of the Hayward manual. LOL But maybe that is meant more for an in-ground install, not an above-ground install?
- Jul 21, 2013
- 52,817
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
25% rule works equally well for in-ground install or above-ground install.
Have you conquered your algae problems?
LOL... yes... and so painful. Haha. So I shocked and flushed and shocked and flushed and finally got all the algae out. Then I went around with a brush to clean the sides and cove area to get the last of it. After I was finishing up my daughter says "Dad, i think the pool is leaking". I go out and near the pump water is gushing out. I look inside and there's a 2" rip right on the cove. I think the edge of my brush must have caught it? I use a Wall Whale and it has a big tail that flips back and forth and it may have hit the liner as I was doing the wall. So I try to tape it (the waterproof gorilla tape is great stuff in times like these) but it had already routed out enough sand that the liner was stretching down into the hole. Blah blah, finally drained the pool, pulled back the liner, added more sand to the low spot, and patched it properly. Refilled it all, then went to do another shock and brush to get the light algae that was starting to bloom while the pool was being re-filled. Got that done and everything looked great. I had backwashed several times so had some standing water, but didn't think much of it. Until three days later there is still standing water. So went in last night and found two more small holes (that yellow florescent leak finding stuff is another awesome product) and patched those with the gorilla tape. This morning no more standing water! Yay! But now I caused a calcium precipitation event. I normally fill with my softened water, but Leslie's was telling me to add 50 pounds of hardness Crud so yeah no... I filled straight from the tap (very high calcium here). Vacuumed it spotless last night, then shocked after the sun went down. With the Cal-Hypo shock. 
Never had a problem before because I was using softened water. But since its full of hard water now this morning my pool looks like it had a lovely snowfall. Hahahahah... Yeah, I love my pool so much. LOL But no more algae! LOL I also gave it the borax treatment - every year I've used that I've had a spotless pool, so hoping for that again this summer. Speaking of, anyone have a lead on Borax tests that actually work? All I can find is the test strips and with three different brands one says the Borax is off the chart, one says its zero, and the third is somewhere in the middle. Hahaha... yeah...
Never had a problem before because I was using softened water. But since its full of hard water now this morning my pool looks like it had a lovely snowfall. Hahahahah... Yeah, I love my pool so much. LOL But no more algae! LOL I also gave it the borax treatment - every year I've used that I've had a spotless pool, so hoping for that again this summer. Speaking of, anyone have a lead on Borax tests that actually work? All I can find is the test strips and with three different brands one says the Borax is off the chart, one says its zero, and the third is somewhere in the middle. Hahaha... yeah...