Variable Speed Pump sizing

Jafarus

Member
May 4, 2020
14
Tennessee
Pool noob in search of the invisible water (something I read and got a kick out of).

Bought a home and both pool pump motors need replacing (corroded, locked up). I have two seperate circuits. One for the in-floor cleaning system (Paramount PV3) and heater (Sta-rite Max E-therm). The other for the filtering system including two skimmers and a main drain. I am focused on the filtering system now. Many considerations with the setup of the pool.
Specifics:
-21,000 gallon gunite pool
-2 skimmer lines and one drain line
-2 inch plumbing everywhere
-Pool pump is 96 piped feet away average between the three suction ports (93,93,103) (when you add the east-west run to the north-south run)
-Skimmers struggle but some of that is due to the weir which I am addressing.
-Filter is a Triton II 100C (rec GPM 74, max gpm 98)
-Pentair IC40 Salt cell pool (minimum 20 gpm, max 80 gpm for the cell)
No flow meter....

A few questions:

1) With the potentially high TDH, should I oversize the variable speed pump I choose to deal with the potentially low flow I find when I do install a flow meter? Not a huge price jump from 1.65, 2HP, to 3HP ($100 to $300)

2) Should I get a pump with Viton/ silicon carbide seals (Hayward VS900, VS950) to deal better with the salt or get the best pump for my situation and install an aftermarket set of seals to deal with salt? Are there other pumps with salt water seals already installed?

3) Should I care about the Pump warranty (Pentair vs Hayward)?

Sorry for the long winded post but I have read enough to make my head explode. Tons of great info on this forum. I appreciate your help.
 
Last edited:

cfherrman

TFP Guide
May 10, 2017
2,527
Hays, Kansas
Get a bigger hp than the pump now, I'd probably go with the 3 unless the gpm is just crazy high. You might beable to have it run both systems as well.

I don't know about the seals but salt is not the big bad evil that people say it is.
 
  • Like
Reactions: Jafarus

jonpcar

Bronze Supporter
Jun 1, 2016
522
Gilbert, AZ
Hey Jafarus...you probably should post some pictures of your system. A few questions:

1) Are you positive of your system’s configuration? A pump to run just the IFCS (separate from the filter) is veerrry unusual, and not the best/standard configuration. To run the IFCS, both pumps would have to be on simultaneously...and then there is a major issue about where your IFCS pump is “drawing” the water from (skimmer, drain, ??). If it is as described, this is probably a hack put in by someone trying to improve the IFCS performance and, having one myself, I don’t think it would work. Is there a leaf basket on your IFCS pump line?

2) Don’t know about the salt...I haven’t seen that issue talked about much, so I assume it is NOT a big concern. The pump experts on this forum will hopefully chime in about your “long runs”. Is each skimmer and main drain plumbed to the pad separately?

3) I’m with cfhermann...I think you should plan on using one pump for both. But that would probably require automation (changing valve positions along with changing pump rpm). For the short term I would recommend that you stick with your plan to get the filtering side working (so you can swim), and ignore the IFCS until you figure out a plan...but that also means no heating for awhile. The bigger VSP will not hurt and would give you an option of hooking up the IFCS at a later time. Some advisors on this board will tell you to abandon the IFCS entirely, and it is good advice in some cases. You’ll have to figure that out.
 
Last edited:
  • Like
Reactions: Jafarus

Jafarus

Member
May 4, 2020
14
Tennessee
I agree with your assessment of the IFCS loop being odd but that is what the pool installer did. The Floor Drain is a multiport drain. One drain is for the IFCS system which is a Paramount Pv3. They put the heater on the loop too so the heat can "rise" from the floor when the IFCS is running. The pump for the IFCS is a standard whisperflo pump with basket. I have thought about putting the whole system on one pump but it may not be worth it to your point (flow balancing issues, auto-valves, etc...). Still doing the math. It is one consideration in the Filter pump size as you stated.

Each skimmer and floor drain is piped seperately. All advice and help is appreciated.

Pool equipment.JPG
 

cfherrman

TFP Guide
May 10, 2017
2,527
Hays, Kansas
So you have a main drain? That can be used for the heater if you want that better heat distribution by sucking from the drains and returning normal. Be aware that using a drain kills the skimmer so most people don't use them.

I would abandon the floor cleaner, use one vsp probably 1.5hp/1.5+, and buy a robot. If you go this route you don't want to cap the floor clear but you have to run water through it from time to time to keep it clean.
 

Jafarus

Member
May 4, 2020
14
Tennessee
@jonpcar
"To run the IFCS, both pumps would have to be on simultaneously...and then there is a major issue about where your IFCS pump is “drawing” the water from (skimmer, drain, ??). "

The previous owner also told me both loops needed to be running if I was to use the IFCS. Why is this?
I'm going to let my Noob roots show on this one.

Thanks again.
 

jonpcar

Bronze Supporter
Jun 1, 2016
522
Gilbert, AZ
Jafrus...IFCSs work like this.:

Stir up the dirt/debris so that the main drain (mostly) and skimmers (debatable, a smaller percentage) can capture the larger debris through the baskets (skimmer basket, pump basket, leaf trap basket if you have it) and the dirt/pollen/sand/small stuff can be taken out by the filter. If you run YOUR IFCS circuit by itself then the only real thing catching some debris is your pump basket (since I am assuming you have no leaf basket). None of the dirt/pollen/sand/small stuff will be taken out...it will just be recirculated through your IFCS pump, through your heater (where it hopefully does not get caught), and then back to your pool. To run the IFCS pump in a normal, effective system is expensive: 1000-1500+ watts (because it requires high pressure/RPM) as compared to skimming/fitering/chlorinating which can be done at lower wattage (with a VSP).

Soooo...in your system you must filter the dirt/pollen/sand/small stuff by running your "filtering circuit" at the same time as the IFCS circuit is running so that you can capture those small particles in your filter WHILE they are suspended/moving by those IFCS popups. AND...you are going to have to run that 2nd pump at a pretty good rate to compete for water with your IFCS pump. You can probably suck about 60% of the water through your filter if you run that filtering circuit pump at a high speed (and wattage). Still, that is going to be about 2X the cost of running the pumps over a standard IFCS system during cleaning.

If your system works well (as many do...I am very happy with mine), the cost may be acceptable. If you aren't happy with the way your system is cleaning, then its a real money loser.

My personal opinion is that IFCSs are most effective & efficient when 1) they have been designed/implemented correctly 2) they are driven by a VSP with appropriate automation for valve manipulation. This would allow a system to run for a few hours at high speed to clean the pool effectively and then at a much lower cost speed to skim/chlorinate.

Without knowing if you would be happy with your IFCS performance, its really tough to make a recommendation. If it were my system, I would NOT run with two pumps...I would reroute some of the piping, and I would add some automation to control a couple key valves along with the VSP pump. The automation will always come in handy (I see you have a water feature), and making appropriate changes would allow you to test your IFCS system in the manner that it should be run. If you don't like it or it doesn't work to your satisfaction, then a robot could be an option.
 
Last edited:

Jafarus

Member
May 4, 2020
14
Tennessee
Jafrus...IFCSs work like this.:

Stir up the dirt/debris so that the main drain (mostly) and skimmers (debatable, a smaller percentage) can capture the larger debris through the baskets (skimmer basket, pump basket, leaf trap basket if you have it) and the dirt/pollen/sand/small stuff can be taken out by the filter. If you run YOUR IFCS circuit by itself then the only real thing catching some debris is your pump basket (since I am assuming you have no leaf basket). None of the dirt/pollen/sand/small stuff will be taken out...it will just be recirculated through your IFCS pump, through your heater (where it hopefully does not get caught), and then back to your pool. To run the IFCS pump in a normal, effective system is expensive: 1000-1500+ watts (because it requires high pressure/volume) as compared to skimming/fitering/chlorinating which can be done at lower wattage (with a VSP).

Soooo...in your system you must filter the dirt/pollen/sand/small stuff by running your "filtering circuit" at the same time as the IFCS circuit is running so that you can capture those small particles in your filter WHILE they are suspended/moving by those IFCS popups. AND...you are going to have to run that 2nd pump at a pretty good rate to compete for water with your IFCS pump. You can probably suck about 60% of the water through your filter if you run that filtering circuit pump at a high speed (and wattage). Still, that is going to be about 2X the cost of running the pumps over a standard IFCS system during cleaning.

If your system works well (as many do...I am very happy with mine), the cost may be acceptable. If you aren't happy with the way your system is cleaning, then its a real money loser.

My personal opinion is that IFCSs are most effective & efficient when 1) they have been designed/implemented correctly 2) they are driven by a VSP with appropriate automation for valve manipulation. This would allow a system to run for a few hours at high speed to clean the pool effectively and then at a much lower cost speed to skim/chlorinate.

Without knowing if you would be happy with your IFCS performance, its really tough to make a recommendation. If it were my system, I would NOT run with two pumps...I would reroute some of the piping, and I would add some automation to control a couple key valves along with the VSP pump. The automation will always come in handy (I see you have a water feature), and making appropriate changes would allow you to test your IFCS system in the manner that it should be run. If you don't like it or it doesn't work to your satisfaction, then a robot could be an option.
I told you I was gonna let my ignorance show. Bottom line, you can run it but you will clean very little and at best you can heat the pool. Yeah this is a mess. The “competing” part you explained is most bothersome. They are both pull from a paramount channel drain with two separate lines. Which means it is just blowing a portion of the the fines right back into the pool.

My only path with two pumps is to tee one of the skimmers to the IFCS and put an autovalve on it to swap when the IFCS is turned on. At that point, why even do it. Just re-pipe to a one pump system with a couple auto valves.

Well thank you. You’ve given me something to chew on.

I guess Im going to look at the two bigger pumps I have eyeballing. They arent much more that the smaller VS pump.
Pentair Intelliflo XF
Hayward Tristar VS 950

I am more than capable of the plumbing and electrical but I have been staring at the warranty issues with self install.
 

jonpcar

Bronze Supporter
Jun 1, 2016
522
Gilbert, AZ
Jafarus...there is another option that I did not mention because I think it is a bit over the top...and I will catch a lot of flak on these boards for even mentioning it (hahaha)...but in truth it is probably the most efficient implementation to operate an IFCS (costwise) albeit at a high up-front cost. But It will not fix a badly designed IFCS (bad placement of heads, mismatches in pressure at the heads, etc).

If you are set on having two pumps, AND add a 2nd filter on your IFCS “circuit”, you would actually have the most efficient IFCS implementation AND potentially (if yours is a good one) the most effective. It would allow you to run the popups to stir up the debris/fine particles AND simultaneously remove it quicker through the filters/baskets...something ALL single pump IFCSs struggle with. It’s a problem for single pump IFCSs because the GPM of a IFCS circuit in operation drops dramatically due to the limitation (head) imposed by those small popup heads which are creating the “sweeping blasts of water”. The lower GPM slows the rate of debris/dust removal...catch 22 scenario. You can turn up the RPM of the IFCS pump to increase GPM, but that is the least efficient part of a VSPs curve and it increases cost/wattage significantly for little GPM gain.

With a 2nd pump (and filter), that entire equation is changed. That 2nd pump could run efficiently in parallel at a much lower wattage (your normal skimming/chlorinating rpm)...and help with the removal of particles. It would probably allow you to run your IFCS circuit for a shorter time to “clean” the pool, although there is a minimum time requirement (it varies but say around an hour) to make a “complete sweep” around the pool, and multiple sweeps are usually required.

Something else I should mention: a heater bypass valve (in my opinion), is almost a requirement for an IFCS system. The pressure lost across the heater dramatically impacts the pressure at your Paramount valve head and forces an even further RPM increase on the IFCS pump to maintain the popup pressure (even higher wattage to run your IFCS). A heater bypass valve is one of the cheapest ways to increase your IFCS efficiency.

By the way..I wish I had a channel drain as you do. That is something I am kicking myself for not including when I replastered my pool. If I got a lot of debris in my pool (which I don’t), I would also put in a leaf debris container between the main drain and the IFCS pump.
 
Last edited:

Jafarus

Member
May 4, 2020
14
Tennessee
Jafarus...there is another option that I did not mention because I think it is a bit over the top...and I will catch a lot of flak on these boards for even mentioning it (hahaha)...but in truth it is probably the most efficient implementation to operate an IFCS (costwise) albeit at a high up-front cost. But It will not fix a badly designed IFCS (bad placement of heads, mismatches in pressure at the heads, etc).

If you are set on having two pumps, AND add a 2nd filter on your IFCS “circuit”, you would actually have the most efficient IFCS implementation AND potentially (if yours is a good one) the most effective. It would allow you to run the popups to stir up the debris/fine particles AND simultaneously remove it quicker through the filters/baskets...something ALL single pump IFCSs struggle with. It’s a problem for single pump IFCSs because the GPM of a IFCS circuit in operation drops dramatically due to the limitation (head) imposed by those small popup heads which are creating the “sweeping blasts of water”. The lower GPM slows the rate of debris/dust removal...chicken/egg scenario. You can turn up the RPM of the IFCS pump to increase GPM, but that is the least efficient part of a VSPs curve and it increases cost/wattage significantly for little GPM gain.

With a 2nd pump (and filter), that entire equation is changed. That 2nd pump could run efficiently in parallel at a much lower wattage (your normal skimming/chlorinating rpm)...and help with the removal of particles. It would probably allow you to run your IFCS circuit for a shorter time to “clean” the pool, although there is a minimum time requirement (it varies but say around an hour) to make a “complete sweep” around the pool, and multiple sweeps are usually required.

Something else I should mention: a heater bypass valve (in my opinion), is almost a requirement for an IFCS system. The pressure lost across the heater dramatically impacts the pressure at your Paramount valve head and forces an even further RPM increase on the IFCS pump to maintain the popup pressure (even higher wattage to run your IFCS). A heater bypass valve is one of the cheapest ways to increase your IFCS efficiency.

By the way..I wish I had a channel drain as you do. That is something I am kicking myself for not including when I replastered my pool. If I got a lot of debris in my pool (which I don’t), I would also put in a leaf debris container between the main drain and the IFCS pump.
If I can get my hands on a used cartridge filter at a good price ($100-$150), This may be a good option. Shouldn't have to cycle the cartridge for cleaning or replacement too often since it will only see a limited load.

I'm not hung up on running two pumps. I would rather run one but after re-piping, auto valves and automation, it may cost more than just putting on the filter you suggest and paying the $10-15/month in electricity...
 

jonpcar

Bronze Supporter
Jun 1, 2016
522
Gilbert, AZ
Actually, for better effectiveness, running two pumps/two filters will cost you significantly less than your existing setup, and less than a 1-pump IFCS. But the costs up front are obviously higher. Your new skimming/chlorinating pump does not need to be large (as cfherrman mentioned), but efficient, and should almost run for “free” (when I am skimming my pump is at 138 watts/30 gpm...900 watts/60 gpm when running the IFCS).

if you decide to pick up a cheap filter, your skimming/chlorinating filter would be the better replacement candidate for it since that circuit would be run almost always at lower pressure...and skimming is more to collect surface materials in the skimmer baskets, not as much for filtering particles. Ideally you would want the larger, better filter on the IFCS to reduce the pressure loss to your popups and increase it’s efficiency. But that could be switched at a later time.

if you give this an attempt, keep us informed...it’s a bit of an experiment, but I am 100% confident that it would perform better than your existing setup, which is totally off base, imo.
 

Jafarus

Member
May 4, 2020
14
Tennessee
Sounds right. THe only thing I've struggled with is the Skimmers (2 each) on this pool are weak. I know I have some weir problems I plan to deal with but in the OP I mentioned my likely high TDH too. What is the lowest GPM you have going through your skimmers? Do you have 1 at 30 gpm or are you running 2 at 30 GPM (15 gpm each).
 

jonpcar

Bronze Supporter
Jun 1, 2016
522
Gilbert, AZ
I run one at 30gpm simply because that is my pump’s most efficient operatimg point and it seems to do the job for my one skimmer. I have seen some people on the forum run as low as 15gpm per skimmer, but that wouldn’t work for my pool.

In the picture your main drain return is “off” (for the filtering side) which should be good for the skimmer flow. Are you using your wall return(s) to start a low speed surface swirl in your pool to carry floating debris directly by the skimmers? That made a huge difference for me...thanks again @Arizonarob ! Also, as you noted, weirs are very important...sounds like you are coming up to speed!
 
Last edited:

Jafarus

Member
May 4, 2020
14
Tennessee
I run one at 30gpm simply because that is my pump’s most efficient operatimg point and it seems to do the job for my one skimmer. I have seen some people on the forum run as low as 15gpm per skimmer, but that wouldn’t work for my pool.

In the picture your main drain return is “off” (for the filtering side) which should be good for the skimmer flow. Are you using your wall return(s) to start a low speed surface swirl in your pool to carry floating debris directly by the skimmers? That made a huge difference for me...thanks again @Arizonarob ! Also, as you noted, weirs are very important...sounds like you are coming up to speed!
I am using my returns but frankly still learning and fine tuning. The skimmers struggle so I dial the main drain (#1) down to almost nothing (just enough to keep pipe clean) and then I tune between the two skimmers to get them about equal. My plan right now is to get the weir to float a little higher by inserting some closed cell foam (material like a pool noodle), to get the surface velocity up. Not even sure I need two skimmers based on what I have read. It was a tricky issue with a single speed pump. No flow meter in the system (yet) but I'm guessing I was getting around 60 gpm at 3450rpm (1HP 1.65 SF motor).

I have another issue I am going to post to the forum on a dead zone in the wading area. No returns in this area the other returns are deeper than the wading area so I can't get any circulation. It is deceptively large for this picture due to the camera angle. It is about 8 ft of the total 32 ft length of the pool, pool is around 20ft wide. Thinking about creative ways to circulate the water using some sort of replacement plug into the current water feature (pop up bubbler insert for Paramount PV3 floor tube, fairly useless). Stuff just gathers over there....Pool features.JPG
 

jonpcar

Bronze Supporter
Jun 1, 2016
522
Gilbert, AZ
I don’t have experience with swirling except for with my pool and I only have 2 returns and 1 skimmer, but here are my thoughts for what they are worth. I agree with you that two skimmers placed so close to each other doesn’t seem optimal. I had trouble creating a surface swirl in my pool because my eyeballs are deep, and were very hard to move to get the positions I needed...slightly pointing towards the surface and as far as I could get them to turn so that they help the swirl (90 degrees would be a goal but not close to possible with standard eyeballs). I believe some people have found alternatives that are better suited.

Your goal is to point ALL your returns slightly up (towards the surface) and in one direction to try and start a clockwise or counterclockwise swirl on your pool’s surface. The best chance of having an impact on your “dead spot” wading area seems to me to be clockwise (building up momentum). Doesn’t hurt to try both ways...I have been told that people use ping pong balls (or equivalent) to track/tune their swirl.

It’s possible you may want to direct “all” (say 95%) of your return suction to one skimmer, something it seems you have considered. Your plan for the bubblers could be a good one if you can find appropriate nozzles that will aid your swirl direction. If your pools water level is correct and the skimmer/weir was installed correctly and is in good working condition, I don’t think you should have to mess with the weir...