Return pump capacity? - Tropical Fish Keeping - Aquarium fish care and resources
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post #1 of 3 Old 07-04-2008, 05:06 AM Thread Starter
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Return pump capacity?

How do I calculate what the return of the sump pump will be?

Tank will be 55gallons.

Sump and refugium combined inside the stand, under the tank.
I will have 2 overflows 1 inch in diameter going down, one going to the sump and one going to the refugium.

I would like to know what output should the return pump have given that the plumbing will probably have one or maybe 2 90degrees turns.
I will try to just have one if I can.

Also how should the water be returned back in the tank?
Should the opening of the pipe(that has the water pumped back in the tank) go over the water level or under it?
Going above water level will probably cause bubbles in the water right?
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post #2 of 3 Old 07-04-2008, 06:38 AM
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The return pump should be closely matched the rating of your overflows. If you are running two 350gph overflows, then you should shoot for about 700 gph. You should plumb a T off of your return line back to the sump with a shutoff valve, that way, if your pump is overrated, you can make adjustments to the flow.

There are several head loss calculators available on the web that can figure in for elbows and such. I recommend the use of two 45 degree elbows as opposed to a single 90 degree elbow. that will cause less head loss.

The return line outlet should be below the surface of the water, and should include a "syphon break" just below the surface. Take a look at the Stickied article at the top of this section for additional explaination.

Yes, going above the water will cause excess microbubbles.

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The Haunting Grounds - SKAustin's Reef Diary - Part 2 (the 75g upgrade)
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post #3 of 3 Old 07-08-2008, 03:21 AM Thread Starter
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Thanks SKAustin.
I have a few more questions I would like to ask on this subject.

I will be building the tank, sump etc on my own.
So people in 2-3 forums suggested I build my sump and refugium together.
One drain from the tank will go to the left part of a secondary tank(sump and protein skimmer) and the second drain will go to the refugium.
In the center, there will be a chamber where I'll keep the return pump.

So here are my questions:
1) Given that I will have a 55 gallon tank with 2 drains that will be 1 inch in diameter(approximately) what will the flow to the sump/refugium be?
How is that flow calculated? There will probably be 2 90 degrees bends, one on each drain(out of the tank horizontal and turn to go downwards to the sump)
I need a way to figure this out so I can choose a pump to match that flow.
Unless I build everything and calculate the flow by timing how long it takes to drain 55gallons so I can find a pump that matches that?

2)Also I'm not sure where exactly the drain holes should be drilled. My initial plans were to drill them 2 inches below water level, so in case of a power outage only that volume of water will flow to the sump so it wont overfill.
I read the sticky thread and I've attached a quick sketch up of a drain that is suggested there. What is your opinion on this one?
If its a good one, can it be used on the width of the tank instead of the length?Or can I make 2 smaller individual chambers?

3)When I finally figure out what the flow is to my sump, I can choose the appropriate pump.
I see you suggested 2 45degrees elbows on the return. I am wondering how will 45 degrees elbows affect the flow from the tank to the sump, or the water pressure is enough and I shouldn't worry about this.

4) People suggest a split connection on the return plumbing where 1 part of the return goes to the tank and the other part goes in the sump again.
They also have a valve on the plumbing that goes in the sump.
I 've also seen this setup in the sticky thread.
Its obvious that the return pump is capable to send more water out than what is going in the sump, so using this kind of setup they adjust the flow so they dont drain the sump, refugium.
Should I do the same? Spend maybe 30-50 dollars more on a pump that can send more water than have a pump that can't cope and use this setup?

5) I've read some posts from people that are using valves on the return plumbing to ensure that in case of a power failure their sump wont overflow. I also read that this kind of valves add 0.5-1 feet of head pressure. I can avoid the use of such a valve by using and maintaining the siphon break you suggested, right?

6) In freshwater aquaria we use airpumps to add oxygen in the water.
Why is this being avoided in marine aquaria?Why do we try to avoid bubbles so much? Do they cause harm in any way or is it because we try to replicate a natural enviroment and those bubbles arent a part of it?

on this kind of overflow, what are the risks of something getting from the main tank in the small chamber/chambers? and blocking the pipe?
How can I keep snails or macroalgea for example from getting in there and blocking the flow?
There are also some covers for the drains (strainers).
I'm sure this have the advantage of not letting larger pieces of algea or snails getting in the pipe and blocking it or going down to the sump, but its easier to get blocked by something.

This is a design I made the last time I was asking questions for sump, refugium and plumbing. Is there anything to improve in this one?
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