I thought I tread something about this somewhere but is there a proper way to size your return pump so that you are optimizing your skimmer? I thought I ready you want your return gph to match the air intake or something like that from your skimmer to get the most out of it.
Sizing a return pump
- Thread starter hiimsean
- Start date
I size return pumps and skimmers to the size of the system, or display, accordingly.
For most skimmers, I de-rate them about 50%. So, if they say 200 gal. with a medium load, I assume that actually means about 100 gal. of system volume capacity.
With return pumps, assuming a traditional single room/level install, with tank about 4 feet above the floor, I assume about 50% loss due to head (height) loss & plumbing/frictional loss. I also target the delivered or actual flow at about 5x’s the tank volume. So, for a 120 gal tank 4 feet above the floor I would choose a pump in the 1000-1200 gallon per hour flow range.
For multi-level homes and/or basement type fish room installs, the considerations and calculations are more complex, but doable with some homework. That is an individual situation type of thing, so beyond the scope of these comments.
AC voltage pumps cost less & generally have better pressure performance. DC pumps are typically variable speed, but don’t handle pressure as well.
Fwiw,
Some AC pumps have a variable intake opening for adjusting the flow. Or, you can add a valve between the input & output of a pump, as a variable bypass, and make it infinitely variable by manually adjusting the valve.
Hope this helps.
For most skimmers, I de-rate them about 50%. So, if they say 200 gal. with a medium load, I assume that actually means about 100 gal. of system volume capacity.
With return pumps, assuming a traditional single room/level install, with tank about 4 feet above the floor, I assume about 50% loss due to head (height) loss & plumbing/frictional loss. I also target the delivered or actual flow at about 5x’s the tank volume. So, for a 120 gal tank 4 feet above the floor I would choose a pump in the 1000-1200 gallon per hour flow range.
For multi-level homes and/or basement type fish room installs, the considerations and calculations are more complex, but doable with some homework. That is an individual situation type of thing, so beyond the scope of these comments.
AC voltage pumps cost less & generally have better pressure performance. DC pumps are typically variable speed, but don’t handle pressure as well.
Fwiw,
Some AC pumps have a variable intake opening for adjusting the flow. Or, you can add a valve between the input & output of a pump, as a variable bypass, and make it infinitely variable by manually adjusting the valve.
Hope this helps.
I aim for 10x turn over in the tank with the return pump, ac pumps generally have higher head pressure to help out with long runs or basement sump. One thing to consider with return pump size as it relates to the skimmer, sump size can affect the efficiency of the skimmer because the same amount of flow goes through your sump. Imagine a 20 gallon sump with 1200gph running through it, they're would be no contact time for the skimmer to get anything from the water.
I also under rate the skimmer ratings advertised as mentioned above.
I also under rate the skimmer ratings advertised as mentioned above.
There are some really good calculators online to determine your head pressure, the older calculators worked the best for us. BRS also has some good videos regarding gph turnover and skimmers. For skimmers, I agree- if it says 500 gallons, I assume 250. You can always dial back and limit hours if your nitrates and phosphates go to low or feed more.
I'm in the 3 to 5 times turn over of the display, not the whole system, camp. Then match the skimmer gph to around a quarter or more of that rate of heavily stocked.
So if you are looking at 1000gph turn over you're looking at a skimmer with 250—300gph of water input. This gives the skimmer a chance to work.
So if you are looking at 1000gph turn over you're looking at a skimmer with 250—300gph of water input. This gives the skimmer a chance to work.
Rather than calculating display tank volume turnover through your sump you pay attention to keeping water in your sump long enough for your skimmer to skim as much of that water as possible.
Grab your skimmer pump GPH rating - reduce that rating by some random guess (I'd probably say 75%). Then - you want a calculator to figure out head pressure on your return pump - heres a page that will assist you with that. https://pentairaes.com/pump-calculator. Try to match them pretty closely.
Your other option is to go with a controllable DC pump or put a T with a valve on your return pump if it's an AC pump. That would allow you to adjust to your situation - skimmer not pulling enough nutrients? slow down your flow through the sump to allow the skimmer to work more efficiently.
Grab your skimmer pump GPH rating - reduce that rating by some random guess (I'd probably say 75%). Then - you want a calculator to figure out head pressure on your return pump - heres a page that will assist you with that. https://pentairaes.com/pump-calculator. Try to match them pretty closely.
Your other option is to go with a controllable DC pump or put a T with a valve on your return pump if it's an AC pump. That would allow you to adjust to your situation - skimmer not pulling enough nutrients? slow down your flow through the sump to allow the skimmer to work more efficiently.
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