Flow rate help

sgterik

Active member
Mar 31, 2020
31
Arizona
Hey all. Thanks for the help in advance. I purchased a house about 1.5 years ago and it came with some pretty old equipment. Has a sand filter that I believe is a Triton TR100 and had old pumps. 2" plumbing. I replaced my old single speed pump with a Hayward Tristar 950 VS with Omni Hub last year and so far love the automation and such I gained. Now, I am trying to work on tuning everything to the speed I need and such. My pool is a decent size at about 30,000+ gallons. ( I filled a set volume and timed it then when filling the pool I multiplied that by time taken to fill) Now here is where I need help. I have always had what I consider pretty high pressure of 30-35 psi on the filter reading depending on what is open and shut and the such. I recently swapped the sand for FilterBalls as well. I put in a flow meter and on highest setting (3450 rpm) I get about 70gpm and on Med (1725) I get about 15-20 gpm. Doesnt that seem really low? Even on high I would have to run my pool about 8 hours just to turn it one time. Also, is it normal that if I bypass the Mastertemp 400 my system pressure lowers about 5 PSI?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
44,310
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Turnover is a myth, so do not worry about that.

Without a SWCG, your main need for the pool pump is to mix the chemicals in when you add them and skim the surface. So adjust the rpm to that needed to skim the surface. If using liquid chlorine, just add it each day when the pump is running.

The heater does increase the system pressure.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
44,310
Laughlin, NV
Pool Size
6000
Surface
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Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Every system has its own pressure. Pipe size, tube turns, valving, return size, etc all impact it.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
44,310
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
One, we have no idea how accurate any flow meter is. Also, at those pressures, your flow would be lower.

Honestly, flow rate does not matter. As long as the system is doing the function that needs to be accomplished, it is not something to make a problem out of.
 

senex

Gold Supporter
Mar 20, 2018
24
Austin, TX
A while ago I had what I considered an inexplicably low flow rate. This forum suggested I do a test with my multiport valve to "recirculate," which bypasses the filter. When bypassing the filter, my flow rate improved dramatically. Thus I disassembled and hosed off the filter, after which the filter flow rate was much improved.

See Disappointed with Intelliflo VSF gpm at low rpms
 
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jonpcar

Bronze Supporter
Jun 1, 2016
595
Gilbert, AZ
Hey all. Thanks for the help in advance. I purchased a house about 1.5 years ago and it came with some pretty old equipment. Has a sand filter that I believe is a Triton TR100 and had old pumps. 2" plumbing. I replaced my old single speed pump with a Hayward Tristar 950 VS with Omni Hub last year and so far love the automation and such I gained. Now, I am trying to work on tuning everything to the speed I need and such. My pool is a decent size at about 30,000+ gallons. ( I filled a set volume and timed it then when filling the pool I multiplied that by time taken to fill) Now here is where I need help. I have always had what I consider pretty high pressure of 30-35 psi on the filter reading depending on what is open and shut and the such. I recently swapped the sand for FilterBalls as well. I put in a flow meter and on highest setting (3450 rpm) I get about 70gpm and on Med (1725) I get about 15-20 gpm. Doesnt that seem really low? Even on high I would have to run my pool about 8 hours just to turn it one time. Also, is it normal that if I bypass the Mastertemp 400 my system pressure lowers about 5 PSI?

sg, as Marty mentioned, with no specifics about your system (pool details in signature and pictures of your control pad) it is very difficult to determine if there is an issue. If your flow numbers are from a FlowVis, they are most likely accurate...if they are from any other consumer flow device, I wouldn’t bet on them.

I “know” my gpm numbers because I have an In-Floor-Cleaning-System and turnover is a part of the equation for run time efficiency (watts/power usage). Also, during swim season I notice issues with water clarity: grasses, pollens, palm threads, etc...all seemingly permanently suspended in the water without filtering...this issue is partly due to my pool surroundings.

If your numbers are accurate AND they represent a circuit that is just filtering water through the skimmers and returning it back through wall returns, then TO ME the gpm numbers DO seem low. There are a lot of caveats in that statement.

Finally, I had a sand filter for a couple decades...I would be very wary of FilterBalls. I did a minimal search and didn’t find anything that I consider to be unbiased reviews of its performance. Senex’s idea (previous post) is a good one if you have that filter capability.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
14,729
Pleasanton, CA
Pool Size
20000
Surface
Plaster
Chlorine
Salt Water Generator
Thanks for responding but I am still looking for info on that flow rate and system pressure.
If you have 1.5" plumbing, then that would be about right. For 2" plumbing, the flow rate is a bit on the low side (pressure on the high side). Are you sure all the plumbing is 2"? How many returns to the pool and what size are the eyeballs? Are there any check valves in the plumbing?
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
8,627
Central California
Pool Size
12300
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Just because you see 2" plumbing above ground doesn't mean it doesn't reduce or tee to 1.5" underground somewhere. And you have no idea how much pipe and how many elbows are buried.

Filter pressure determines your filter cleaning interval. You say it went down right after you cleaned it (as expected). So that would be your clean-filter pressure reading. You clean (or backwash) a pool filter when it reaches 20% higher than its clean-filter pressure reading. Simple as that. If that happens often, then so be it. Something is getting into your water that requires that interval.

You've already changed your filter media, and you're not going to tear up your yard in search of some sort of plumbing restriction. Done. If your pool isn't leaking and your water is staying clear, then your system is working. As Marty points out, if it ain't broke, don't fix it.

If you're still not satisfied, hire a plumber to run a camera through all your pipes.
 

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sgterik

Active member
Mar 31, 2020
31
Arizona
sg, as Marty mentioned, with no specifics about your system (pool details in signature and pictures of your control pad) it is very difficult to determine if there is an issue. If your flow numbers are from a FlowVis, they are most likely accurate...if they are from any other consumer flow device, I wouldn’t bet on them.

I “know” my gpm numbers because I have an In-Floor-Cleaning-System and turnover is a part of the equation for run time efficiency (watts/power usage). Also, during swim season I notice issues with water clarity: grasses, pollens, palm threads, etc...all seemingly permanently suspended in the water without filtering...this issue is partly due to my pool surroundings.

If your numbers are accurate AND they represent a circuit that is just filtering water through the skimmers and returning it back through wall returns, then TO ME the gpm numbers DO seem low. There are a lot of caveats in that statement.

Finally, I had a sand filter for a couple decades...I would be very wary of FilterBalls. I did a minimal search and didn’t find anything that I consider to be unbiased reviews of its performance. Senex’s idea (previous post) is a good one if you have that filter capability.
Thanks for the input. I am using a FlowVis. I did notice that my pressure gauge was wrong and i am only at about mid 20's. The GPM is through 1 skim basket. It doesnt seem to change if I switch and open the side suction vac. I just wish I had more flow so I could run the pump at lower speeds. Having a larger pool of 30,000 plus gallons I would prefer to be getting more and it seems like I should .

On another note, is it normal for a pump to take a while to not have air in the pump basket area and the Sand Filter every time it starts up?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
44,310
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
On another note, is it normal for a pump to take a while to not have air in the pump basket area and the Sand Filter every time it starts up?
No. That sounds like you have a leak somewhere letting the system drain out when the pump is off.
 

jonpcar

Bronze Supporter
Jun 1, 2016
595
Gilbert, AZ
If you have 1.5" plumbing, then that would be about right. For 2" plumbing, the flow rate is a bit on the low side (pressure on the high side). Are you sure all the plumbing is 2"? How many returns to the pool and what size are the eyeballs? Are there any check valves in the plumbing?

Mark, sg’s high rpm numbers (75 gpm) do seem more consistent with 1.5” equivalent numbers...if it were my system I would be most concerned with the low numbers: 1725rpm and getting only 15-20gpm. Isn’t that flow rate “on the edge” for many SWGs/skimmers being consistently operational? ...which in turn would push his minimum rpm run requirements up even higher (1800/1900+ ??). It seems higher than the requirement of most posters in the forum...at least that I have noticed.

sg, glad you found and fixed one issue with your psi gauges...we still know almost nothing about your system: no specs, no pictures. If you are continuing your “investigation”, you currently have a few of the most experienced eyes in the forum (I am definitely not one of them, haha). They have all helped me many times in the past...good luck.
 
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