30 Gallon Tank Idea for a sump.....

FreshWaterFun

Member
OK I only have a thirty gallon tank so its nothing to crazy or anything, I have an idea for a sump. My tank is already filled with various life forms and everything is doing fine, I'm just getting bored and want to establish a better living experience for my fish friends. From what I understand people already have a drilled tank, which mine is not and I don't want to do since my tank is already up and running. Or they put in an overflow using a siphon to drain the water into the sump tank, please correct me anywhere I'm wrong. Ive been researching and also heard stories from close friends who had them,about the siphon in these overflows can get air trapped and then ull be pumping water out of the sump but not back in. Apparently this happens more often than I'm looking to do myself. Once the water is in the sump we then push it out of the sump back into the tank right? Well, heres my idea and I'm not sure it would work but a pump basically sucks in water and then pushes it out, so could I just get two pumps one to suck water out of my tank and into my sump, let the sump fill up a bit and get another pump to push it back out into my tank? It seems in my head and I'm no scientist that this would work as long as both pumps were set the same, like the gallons per hour they push out and hose size? So if I get two identical pumps same everything and I'm probably going to be using a 15 gallon tank and say fill the tank to about ten gallons and as long as the pumps are the same. One would be sucking water out of the tank and pushing it into the sump just for instance we will say 50 gallons per hour and I have a second pump on the other side of the tank sucking up the water and pushing it into my tank at 50 gallons per hour it seems like it would work. Then I would just have to hide the tubes and everything but it would be better than mopping up a huge puddle if my siphon didnt work and it beats having to disassemble my tank to drill holes in it. Please any imput would be well appreciated like I said I'm no scientist I was just thinking and thought this might work but I haven't seen anyone try it before so I don't know if someone tried it and found it won't work. Again thank you for any imput and advice
 

travie

Member
Your theory doesn't factor in gravity. Your two identical pumps won't be pumping at the same GPH due to gravity. Best way to connect a display tank with a sump tank is to use an like the one in the link. Then get a pump rated for slightly less GPH then the Overflow box's GPH.
 
  • Thread Starter

FreshWaterFun

Member
Sorry my computer won't go to the website you provided. But I have found a few overflow boxes on other websites, the only thing is how do I know what size pump I should get for the return line to the tank?? Also what are some of the common reasons a the siphon would get air trapped? One would probably be too little water going into the overflow, right?
 

travie

Member
Yes that would be one reason for air to get trapped in the U-Tube. To elaborate on that; the water needs to be moving fast enough to take the air bubbles all the way through the U-Tube. Lets say the overflow box is rated for 1000 GPH. You will want to get a pump rated for less than 1000 GPH.
 
  • Thread Starter

FreshWaterFun

Member
What would you recommend to be good for my thirty gallon tank and I have at my disposal a 10 gallon and also a 15 gallon tank for the sump that might actually be 20 gallons ive never measured. Either way if you wouldnt mind making a suggestion on a good size overflow and proper return pump that would be greatly appreciated
 

au01st

Member
You generally want 5x the tank volume running through the sump, so a 30 gallon tank would want about 150gph flow from the pump, but you have to account for head pressure (the height needed to return the water to the tank). Do you know how high the display will be above the sump? As that will factor in to your return pump choice.

There are misconceptions about overflow boxes. If set up properly, there will be no worries about the siphon breaking or either tank overflowing/running dry.

Check out this . I have the 800gph model and it has been flawless. Not a bad price either.

Set that up with some 3/4" PVC, a Hofer Gurgle Buster or Stockman Standpipe, and you're good on the overflow side. Find a pump rated for 300gph with 0 head, and you should be set, as the head pressure will not allow the pump to push more than the overflow box can handle. It's really hard to explain how the whole thing works, but once it's set up, it makes sense why it won't overflow or run dry.
 

cerianthus

Member
Common 1" U-tube is rated to drain about 600GPH, if memory serves. Used mag 7 w/ 1" u-tube Overflow Box w/o problem on many tank since Head Pressure will recuce the pump's capacity.
As far as air pocket forming in the center top of U-tube, this will reduce drain capacity. Even when used Mag 7, still trapped microbubbles which will eventually form air pocket.

Check my dwg (terrible handwriting and dwg) to see if this will help you as it helped me.

Good Luck!! LMK if have problem reading, will do another, better DWG for you.

This check valve sure beats shaking u-tube to rid of air pocket. If U-tube is raised too much during shaking, will loose prime and will have flood unless pump is unplugged fast.
Been using this DIYcontraption since late 80 w/o any problems.
As they say, Necessity is Mother of Invention!!! LOL
 

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