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Return pump question


jon_703

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I have a 75g and will be running an overflow box and obciously a sump. How strong ahould the return pump be? Is 400gph enough?

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You'll have to consider head friction losses through the plumbing. Many pump manufacturers provide curves for their pumps that you can use to determine head losses. If you have narrow plumbing running a lengthy, circuitous route, you can lose a whole lot of flow and that 400 gph pump may quickly become a 200 gph pump, or even less. So, as a starting point, let's say that you target a turnover rate of 3-4x your system volume. Let's also assume that you have 100 gallons total (of actual water in the system). In this case, you're looking at being able to deliver 300-400 gph without head or friction losses. So, most likely, you'll want a pump that's sized a bit larger for this turnover rate.

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You'll have to consider head friction losses through the plumbing. Many pump manufacturers provide curves for their pumps that you can use to determine head losses. If you have narrow plumbing running a lengthy, circuitous route, you can lose a whole lot of flow and that 400 gph pump may quickly become a 200 gph pump, or even less. So, as a starting point, let's say that you target a turnover rate of 3-4x your system volume. Let's also assume that you have 100 gallons total (of actual water in the system). In this case, you're looking at being able to deliver 300-400 gph without head or friction losses. So, most likely, you'll want a pump that's sized a bit larger for this turnover rate.

Once again Origami you very informative! My plumbing will be straight into the actual output head. The output head has a few angles. That should be ok right?

 

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As above, you'd be surprised at how much pressure loss you get with just a single elbow (or even an open valve). My DT is also a 75 with an overflow box (CPR 102), and it was originally running off an Eheim 1260 (rated 635 gph). I'm now running a MAG 12 (1200 gph), but taking a significant chunk of that off for media reactors. So I'd suggest something of at least 600 gph.

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What make/model pump are you considering? Maybe we can find a flow curve for it.

 

What size return plumbing are you planning on using? 3/4" will give a lot of loss. 1" can be lossy, too. 1-1/4 and 1-1/2 are both better choices, even if you have to use adapters at either end to make connections. Think of plumbing as a little bit like electrical wiring - thin (narrow) wires can get warm or even hot (that is, they dissipate energy and are "lossy") when current (analogous to water flow) is high. Thicker wire will run cooler (less lossy). The same thing happens with plumbing and friction losses. Elbows, tees and the like will cause additional losses.

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What make/model pump are you considering? Maybe we can find a flow curve for it.

 

What size return plumbing are you planning on using? 3/4" will give a lot of loss. 1" can be lossy, too. 1-1/4 and 1-1/2 are both better choices, even if you have to use adapters at either end to make connections. Think of plumbing as a little bit like electrical wiring - thin (narrow) wires can get warm or even hot (that is, they dissipate energy and are "lossy") when current (analogous to water flow) is high. Thicker wire will run cooler (less lossy). The same thing happens with plumbing and friction losses. Elbows, tees and the like will cause additional losses.

Got this!

 

Going to rig my own neck into the tank so there aren't so many bends. It'll just flow straight in with out any bends.

 

b5d6bc561c7f7c8f59d44a5ba03d74c5.jpg

 

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So, max head is 94" - that means the pump will lift and hold a column of water (probably fresh water) up to 94" before it comes to a complete stop. 91 inches for salt water since it's heavier by volume. Capacity is 608 gph at 0" of lift. It has a 3/4"output and comes with a 1" adapter. Aqueon provides no flow curves for the pump, so that's going to be an unknown risk. So, for now, let's assume that the pump will deliver half its flow capacity at 2/3 of the max head. This assumption results in 304 gph at about 60 inches (or 5 feet) BEFORE friction losses are accounted for.

 

Friction losses can be substantial but let's assume that you're using 1" pipe and that it takes about 5% of your flow away from you. That brings the estimate down to about 290 gph. This may not be accurate for this particular pump, but it serves to illustrate how expectations need to be moderated.

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So, max head is 94" - that means the pump will lift and hold a column of water (probably fresh water) up to 94" before it comes to a complete stop. 91 inches for salt water since it's heavier by volume. Capacity is 608 gph at 0" of lift. It has a 3/4"output and comes with a 1" adapter. Aqueon provides no flow curves for the pump, so that's going to be an unknown risk. So, for now, let's assume that the pump will deliver half its flow capacity at 2/3 of the max head. This assumption results in 304 gph at about 60 inches (or 5 feet) BEFORE friction losses are accounted for.

 

Friction losses can be substantial but let's assume that you're using 1" pipe and that it takes about 5% of your flow away from you. That brings the estimate down to about 290 gph. This may not be accurate for this particular pump, but it serves to illustrate how expectations need to be moderated.

Ahhhh. They guy i got it from said it will be good enough. The water is only traveling 3 ft. Hmmm i guess ill have to see what happens.

 

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Ahhhh. They guy i got it from said it will be good enough. The water is only traveling 3 ft. Hmmm i guess ill have to see what happens.

 

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3 feet is not much. You'll get more flow with less vertical lift, so that's good. Sounds like it may work.

 

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3 feet is not much. You'll get more flow with less vertical lift, so that's good. Sounds like it may work.

 

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Soooo im tryingggg to set this up seems that my pump is puming water out faster than its coming in. Im running the eshopps overflow box that has two outlets, i plugged one because my sump only has on intake.

 

Any ideas?

 

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What pump are you currently using? You can put a ball/gate valve at the output and just close it down to slow the flow from the pump.

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What pump are you currently using? You can put a ball/gate valve at the output and just close it down to slow the flow from the pump.

Aqueon 2300

 

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When you say it's pumping faster than the overflow is returning, is the water level building up too high in the tank? If not, you may need to add water to account for the extra water that is now in the plumbing.  If this is already accounted for, then, yeah, either put a ball valve on it or install the plumbing on the other part of the overflow since it sounds like you're only using 1/2 of the output it's capable of.

 

Really, though, there's hardly a reason why your overflow should not be able to handle a 300 gph flow unless it's constricted somewhere. Look closely to see if there's a big trapped air bubble in the overflow that's restricting how much water it's carrying over. 

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And now my skimmer stopped working. Fml.

 

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What do you mean, "stopped working?" Pump stopped? No bubbles?

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Soooo im tryingggg to set this up seems that my pump is puming water out faster than its coming in. Im running the eshopps overflow box that has two outlets, i plugged one because my sump only has on intake.

 

Any ideas?

 

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You should use both of the 2 drains of the overflow box. 1" drain from the overflow box will only get around 150-200GPH (300gph if it goes straight down with no elbows). Also, the second drain will act as a emergency drain in case there is a clog or blockage on one of the drain line. 

the eshopps overflow box SHOULD have 2 wing nuts on the inner box that allow you to raise or lower the box. lowing it will allow more flow into the box and increase the flow as well as lower your water line in the tank so that you can increase/adjust the return flow.

 

Also, as Eric suggested, add a valve on the pump to allow you to adjust the return flow. 

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What do you mean, "stopped working?" Pump stopped? No bubbles?

I unplugged it for a second and plugged it back in then nothing happened. :(

 

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You should use both of the 2 drains of the overflow box. 1" drain from the overflow box will only get around 150-200GPH (300gph if it goes straight down with no elbows). Also, the second drain will act as a emergency drain in case there is a clog or blockage on one of the drain line.

the eshopps overflow box SHOULD have 2 wing nuts on the inner box that allow you to raise or lower the box. lowing it will allow more flow into the box and increase the flow as well as lower your water line in the tank so that you can increase/adjust the return flow.

 

Also, as Eric suggested, add a valve on the pump to allow you to adjust the return flow.

But my sump can only has one intake for a hose.

 

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But my sump can only has one intake for a hose.

 

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it should not be too hard to add another hole in the sump! to me it's better to be safe than sorry.

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it should not be too hard to add another hole in the sump! to me it's better to be safe than sorry.

See one hole.

 

ca372fc44555491e7d06823a43453aef.jpg

 

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If you don't want to drill. Run the second drain "emergency" into the middle chamber. make a stand pipe (drain) in the overflow box a bit higher than the main drain. That way it only drain in case of blockage on the main drain. 

BTW were you able to increase the flow on the single drain? I used HOB ways back and only way to get more flow on a 1" drain is to get full siphon and it not easy to do with this type of overflow box design. Also, type of bulkhead and pipe varies the flow as well (but not a whole lot).  schedule 80 has thicker wall so inner diameter is smaller than the inner diameter of the schedule 40. I like furniture grade pipe for drain, but it is a bit noisier than the schedule 40.

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Take the pump off. Soak it in some vinegar. Take impeller out and scrub it with a toothbrush.

It worked!!! Lol

 

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