Two pumps, two tanks, one sump

Brian Kracht · Oct 4, 2017

Ok so the title definitely sounds like something not PG but it is exactly what my question will be.

I see no real problems with this but I have a large sump I will be using for two separate tanks to connect them. Both tanks near 50 gallons. I do not have a single pump strong enough for both of these tanks to run off from the sump but I do have two pumps strong enough for each separate tank.

I assume the flow rate of each individual pump flowing to it's respective tank will also accompany an appropriate flow rate back to the sump leaving me with no real problems. Does this make sense and does anyone see problems with this potential design?

mcarroll · Oct 4, 2017

Separate drains and return pumps is fine.

Although how big is your biggest pump? (make and model if you know it)

mcarroll · Oct 4, 2017

I run a system that's very similar to what you're planning....check it out:
mcarroll's 100 Gallon System

Kyl · Oct 4, 2017

I had a thread similar to this, everyone seemed to think it would work fine with a few examples. Eventually I'll be doing that with two separate pumps too as I hate manifolds off the tank return, but will plumb them together (but the link shut off) so they can operate in a manifold should one pump fail. At least both tanks could have some reduced flow versus one stuck in limbo while getting another pump in.

ca1ore · Oct 4, 2017

Multiple tanks off a single sump is fine - they're self regulating - as long as the sump is big enough to handle the overflow. I currently run 4 different tanks into my one (large) sump.

BZOFIQ · Oct 4, 2017

You're good to go. As previous poster mentioned, make sure its big enough to handle overflow water from BOTH tanks when pumps are switched off or power is lost.

Brian Kracht · Oct 4, 2017

Thank you for the replies. I have two tanks around 50 gallons. They will be connected to a sump that is 30x16x14. I haven't calculated the volume of that but the seller said it was rated to support 150 gallons of water volume or something like that. I will obviously have to do some practice runs with the whole thing shut off to see if it handles it. One pump will be a mag drive 9 I believe and the other pump will be a Sicce 3.0 which I know will give low amounts of turnover for a 50 gallon tank I think, but it will be what I have.

Brian Kracht · Oct 4, 2017

mcarroll said:
I run a system that's very similar to what you're planning....check it out:
mcarroll's 100 Gallon System

Thank you, I will check that out!

Kyl said:
I had a thread similar to this, everyone seemed to think it would work fine with a few examples. Eventually I'll be doing that with two separate pumps too as I hate manifolds off the tank return, but will plumb them together (but the link shut off) so they can operate in a manifold should one pump fail. At least both tanks could have some reduced flow versus one stuck in limbo while getting another pump in.

I will check out that thread too. I did a pretty lazy search before posting...

mcarroll · Oct 5, 2017

Brian Kracht said:
One pump will be a mag drive 9 I believe and the other pump will be a Sicce 3.0 which I know will give low amounts of turnover for a 50 gallon tank I think, but it will be what I have.

Either of those is overkill – definitely run both tanks from one pump for simplicity. (Unless running two is simpler in your case for some reason!

)

An "online backup" like you described is great, but as long as you have an on-site backup with identical plumbing to the "live" return pump, you're good to go. With an on-site backup, all you have to do is be there – unscrew the dead one, screw in the good one. Troubleshoot/order a replacement in your spare time.

;Brb

Unless your talking about an unattended installation where you won't be there every day, this is more than enough backup planning IMO.

Get a UPS with your remaining backup funds/after selling the spare pump(s). Power outages can be an even bigger problem than equipment failure!

So your existing pumps are fine to keep, but you could easily downsize 1-2 sizes and save size and power – regardless of brand. Might give you funds for a different purchase too.

FYI
I've run my system's return off of a Quiet One 2200 for most of its history (an older Italian model c.2006?), but it's also had a Mag 7 and Quiet One 4000 as a return for significant stretches.

Neither of the bigger pumps (700 and 900 gph, respectively) seemed "better" for the system than the older, smaller pump (600 gph). I do have small diameter plumbing....about 1/2 due to fittings, so never got close to 100% flow from the bigger pumps.

I still have all three pumps, although I had to get a replacement for the 4000 about a year ago...after about 4+ totally, utterly silent years of service. I haven't swapped the 2200 back out since it went from backup to live.

And I've replaced the impellers on the older pumps once. (That Mag7 is really old!)

Brian Kracht · Oct 5, 2017

mcarroll said:
Either of those is overkill – definitely run both tanks from one pump for simplicity. (Unless running two is simpler in your case for some reason! )

An "online backup" like you described is great, but as long as you have an on-site backup with identical plumbing to the "live" return pump, you're good to go. With an on-site backup, all you have to do is be there – unscrew the dead one, screw in the good one. Troubleshoot/order a replacement in your spare time. ;Brb

Unless your talking about an unattended installation where you won't be there every day, this is more than enough backup planning IMO. Get a UPS with your remaining backup funds/after selling the spare pump(s). Power outages can be an even bigger problem than equipment failure!

So your existing pumps are fine to keep, but you could easily downsize 1-2 sizes and save size and power – regardless of brand. Might give you funds for a different purchase too.

FYI
I've run my system's return off of a Quiet One 2200 for most of its history (an older Italian model c.2006?), but it's also had a Mag 7 and Quiet One 4000 as a return for significant stretches.

Neither of the bigger pumps (700 and 900 gph, respectively) seemed "better" for the system than the older, smaller pump (600 gph). I do have small diameter plumbing....about 1/2 due to fittings, so never got close to 100% flow from the bigger pumps.

I still have all three pumps, although I had to get a replacement for the 4000 about a year ago...after about 4+ totally, utterly silent years of service. I haven't swapped the 2200 back out since it went from backup to live. And I've replaced the impellers on the older pumps once. (That Mag7 is really old!)

Wow thanks for the advice, you you are thinking I could easily run both tanks off just that mag nine? Then I can just save the sicce 3.0 as a backup to replace it in case something goes wrong as a good idea. I figured 900 or so GPH wouldn't be enough to split off to two tanks. Once plumbing is taken into account and all.

mcarroll · Oct 5, 2017

Brian Kracht said:
I figured 900 or so GPH wouldn't be enough to split off to two tanks. Once plumbing is taken into account and all.

It might even be a bit much, so I'd have a valve installed at the pump or wherever it's convenient in order to dial it back if needed.

If the sump is under the tank and you use 3/4" or larger plumbing, you can pretty much go by the flow curve from the mfgr to predict your actual GPH through the sump.

Brian Kracht · Oct 5, 2017

mcarroll said:
It might even be a bit much, so I'd have a valve installed at the pump or wherever it's convenient in order to dial it back if needed.

If the sump is under the tank and you use 3/4" or larger plumbing, you can pretty much go by the flow curve from the mfgr to predict your actual GPH through the sump.

I plan to run 3/4 all the way through the tank. Return and drain. So I would be fine just throwing a Y into the return line and running one to one tank and one to the other. So if I put a valve right before that and then limit the flow, would that put extra strain on the pump? Will it decrease it's life? Or will I have extra stress on it causing more heat?

mcarroll · Oct 7, 2017

No stress or extra heat.

But here are some numbers to get a step away from theory before you start buying parts.

Assuming you have:

a grand total of 10ft of plumbing length to get from the pump to the outlets (conservative?)
Anywhere from 4-6 vertical feet between the sump and the top of the tank

First lets look at the Mag 9.5...(the flow curve is in the manual)

PONDMASTER 950GPH MAGNETIC DRIVE PUMP

They say with between 4-6 feet of vertical you could expect from 700-800 GPH under otherwise-unrestricted conditions.

My favorite friction loss calculator says there'd be almost +5 feet of head loss from a 3/4" setup:

Liquid Friction Pressure Loss
Pressure Loss (psi): 2.04 Head Loss (ft): 4.6
Line Number: 3/4"; 11 GPM (660GPH)
Date: 10/7/2017
Nominal Pipe Size: 0.75
Pipe Schedule: SCH 40
Flow Rate (gpm): 11
Viscosity (cP): 1
Specific Gravity (water=1): 1.025
Temperature (F): 79
Pipe Roughness (ft): 0.000016
Actual Pipe ID (in.): 0.824
Fluid Velocity (ft/sec): 6.62
Reynolds Number: 43274
Flow Region: Turbulent
Friction Factor: 0.022
Overall K: 6.75
Piping Length (ft): 10
Short Radius Elbows: 2
Tee Flow Through: 1
Pipe Exit : 2

We'll average your 4-6 feet of verical to 5 feet. 5+4.6 is about 10 feet of head pressure.

According to the Danner curve, 10 feet of head pressure would drop actual flow down to 400 GPH.

400/100 gallons = 4X turnover. My usual max. target....still totally acceptable.

But if you upgrade to 1" or 1.25" you can get a lot closer to the pumps ideal flow rate. Here's the calculator results with only the plumbing size changed:

Liquid Friction Pressure Loss
Pressure Loss (psi): 0.7 Head Loss (ft): 1.6
Line Number: 1"; 11 GPM (660GPH)
Date: 10/7/2017
Nominal Pipe Size: 1
Pipe Schedule: SCH 40
Flow Rate (gpm): 11
Viscosity (cP): 1
Specific Gravity (water=1): 1.025
Temperature (F): 79
Pipe Roughness (ft): 0.000016
Actual Pipe ID (in.): 1.049
Fluid Velocity (ft/sec): 4.09
Reynolds Number: 33993
Flow Region: Turbulent
Friction Factor: 0.023
Overall K: 6.05
Piping Length (ft): 10
Short Radius Elbows: 2
Tee Flow Through: 1
Pipe Exit : 2

Liquid Friction Pressure Loss
Pressure Loss (psi): 0.21 Head Loss (ft): 0.5
Line Number: 1.25"; 11 GPM (660GPH)
Date: 10/7/2017
Nominal Pipe Size: 1.25
Pipe Schedule: SCH 40
Flow Rate (gpm): 11
Viscosity (cP): 1
Specific Gravity (water=1): 1.025
Temperature (F): 79
Pipe Roughness (ft): 0.000016
Actual Pipe ID (in.): 1.38
Fluid Velocity (ft/sec): 2.36
Reynolds Number: 25839
Flow Region: Turbulent
Friction Factor: 0.025
Overall K: 5.47
Piping Length (ft): 10
Short Radius Elbows: 2
Tee Flow Through: 1
Pipe Exit : 2

Sicce has a flow chart on their website that you can use to run the same numbers.

Brian Kracht · Oct 7, 2017

mcarroll said:
No stress or extra heat.

But here are some numbers to get a step away from theory before you start buying parts.

Assuming you have:

a grand total of 10ft of plumbing length to get from the pump to the outlets (conservative?)

Anywhere from 4-6 vertical feet between the sump and the top of the tank

First lets look at the Mag 9.5...(the flow curve is in the manual)

PONDMASTER 950GPH MAGNETIC DRIVE PUMP

They say with between 4-6 feet of vertical you could expect from 700-800 GPH under otherwise-unrestricted conditions.

My favorite friction loss calculator says there'd be almost +5 feet of head loss from a 3/4" setup:

Liquid Friction Pressure Loss
Pressure Loss (psi): 2.04 Head Loss (ft): 4.6
Line Number: 3/4"; 11 GPM (660GPH)
Date: 10/7/2017
Nominal Pipe Size: 0.75
Pipe Schedule: SCH 40
Flow Rate (gpm): 11
Viscosity (cP): 1
Specific Gravity (water=1): 1.025
Temperature (F): 79
Pipe Roughness (ft): 0.000016
Actual Pipe ID (in.): 0.824
Fluid Velocity (ft/sec): 6.62
Reynolds Number: 43274
Flow Region: Turbulent
Friction Factor: 0.022
Overall K: 6.75
Piping Length (ft): 10
Short Radius Elbows: 2
Tee Flow Through: 1
Pipe Exit : 2

We'll average your 4-6 feet of verical to 5 feet. 5+4.6 is about 10 feet of head pressure.

According to the Danner curve, 10 feet of head pressure would drop actual flow down to 400 GPH.

400/100 gallons = 4X turnover. My usual max. target....still totally acceptable.

But if you upgrade to 1" or 1.25" you can get a lot closer to the pumps ideal flow rate. Here's the calculator results with only the plumbing size changed:

Liquid Friction Pressure Loss
Pressure Loss (psi): 0.7 Head Loss (ft): 1.6
Line Number: 1"; 11 GPM (660GPH)
Date: 10/7/2017
Nominal Pipe Size: 1
Pipe Schedule: SCH 40
Flow Rate (gpm): 11
Viscosity (cP): 1
Specific Gravity (water=1): 1.025
Temperature (F): 79
Pipe Roughness (ft): 0.000016
Actual Pipe ID (in.): 1.049
Fluid Velocity (ft/sec): 4.09
Reynolds Number: 33993
Flow Region: Turbulent
Friction Factor: 0.023
Overall K: 6.05
Piping Length (ft): 10
Short Radius Elbows: 2
Tee Flow Through: 1
Pipe Exit : 2

Liquid Friction Pressure Loss
Pressure Loss (psi): 0.21 Head Loss (ft): 0.5
Line Number: 1.25"; 11 GPM (660GPH)
Date: 10/7/2017
Nominal Pipe Size: 1.25
Pipe Schedule: SCH 40
Flow Rate (gpm): 11
Viscosity (cP): 1
Specific Gravity (water=1): 1.025
Temperature (F): 79
Pipe Roughness (ft): 0.000016
Actual Pipe ID (in.): 1.38
Fluid Velocity (ft/sec): 2.36
Reynolds Number: 25839
Flow Region: Turbulent
Friction Factor: 0.025
Overall K: 5.47
Piping Length (ft): 10
Short Radius Elbows: 2
Tee Flow Through: 1
Pipe Exit : 2

Sicce has a flow chart on their website that you can use to run the same numbers.

You seem like the type of person I need in my reef life haha. I appreciate the calculations and work you put in on that.

jeep.ster · Sep 29, 2024

mcarroll said:
I run a system that's very similar to what you're planning....check it out:
mcarroll's 100 Gallon System

I'm running two 55 gallon tanks, each tank has a submersible pump moving 2000 litters an hour I connected both pumps using 1/2 inch clear poly pipe into a 4 gallon diy bucket water filter. Water comes in at top goes all the way down to the bottom comes back up threw ceramic golden filtration balls to the top then glows out threw a 1/2 inch pipe out the bottom into a T which flows into two top tank filter boxes, one on each tank then back into the tank to do it all over again. Only problem was it was harder than hell to regulate the flow evenly for both tanks so that i was not taking from one tank and filling the other