Sump Questions

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Gauge

Aquarium Advice FINatic
Joined
Jul 15, 2003
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Dallas, TX, USA
DIY sump out of a 10-gallon tank

So, they tell me that a CPR backpack filter and 15 pounds of live rock are insufficient for a 42 gallon tank. Well, I'm poor, and I have a 10-gallon tank to spare. I'm toying with the idea of a homemade sump for the tank. Anyone got any suggestions, general input, or sources of information for me? :)
 
I'm thinking about putting a sump on my 42 hex tank. Supposedly the backpack filter I have on there is not cutting it and I don't really want to add more rock (I like open swimming room for my fish).

Anyway, I don't really know a great deal about them. I know the general principles of how they work, I believe, but I'm not sure about a few things in particular...

1) How to balance the intake from the siphon with the output from the pump (is there some math you can use to determine what to do on this?)
2) What kind of work and/or materials are needed for your overflow cup? How big of one do you need? I just want to have it up top on the back side of the tank. Do they just hang on the side or something?
3) Does having a "brand name" sump matter at all? I've seen a few on sale online that are pretty darn cheap. They seem to be a box with compartments basically, so I can't see how they can bet terribly different. However, I know looks can be deceiving, so I'm asking the experts.

Educate me! :D
 
1) Your overflow will keep up with your pump's return volume. The only exception would be an overflow that maxes out at 700 gph and a pump that pumps 1000gph at 4' head. In a case like this, you'd need to install a ball valve on the return line to limit the pump's flow. Get a pump that does 500-600 gph at 4' head and you'll be fine.

2) I've looked into making my own overflow, and for all the hassle it's easier to spend $50 online for a cheapy overflow like an Amiracle.

3) If you want to go cheap, the square 4.5 gallon buckets that pizza shops get their mushrooms in fits perfectly into a 10 gallon tank. I'm guessing that a 6 gallon round bucket would drop into a 20 long...
 
a sump is merely a container for water ... if you're not concerned with appearances, you can use a plastic "rubbermade" container, 30 to 50 gallon capacities are available, on sale they're under $20

well, over the back overflows use a siphon to supply water to the drain, but the siphon itself only equalizes the tank level with the level set by the overflow's weir. the drain will only drain water as quickly as it is supplied by the pump.

matching your overflow's capacity with your pump's rated GPH will ensure that the pump receives a constant supply of water and does not "starve". If your pump is less than your overflow's capacity, you are fine, however, if your pump exceeds the rate at which water can be returned to the pump, it will quickly pump the sump dry, and then shut down (or burn out)

the compartments inside the sump are to form areas for trapping bubbles, placing filter media, and or rock/sand as in a refugium. others may have room for a skimmer, heaters, dosers, etc..

this is about all I know regarding sumps, given my experiements in freshwater sumping ... marine hobbiests may have additonal info regarding using a sump in a marine enviroment.
 
Oh, okay. I think I am just now realizing a misconception that I was having. You don't have to balance the siphon vs. the pump as long as the pump doesn't run dry. All you have to do to keep the sump from overflowing is making sure that you don't have more water than you can have in the tank up to the overflow line and the volume of your sump combined. Duh!

I'm thinkin' about just buying one because I don't have a lot of room, and I'd just like to make sure that what I have works. Is there such a thing as too BIG of a sump for your tank?

Thanks for the help. 8)
 
Gauge said:
Oh, okay. I think I am just now realizing a misconception that I was having. You don't have to balance the siphon vs. the pump as long as the pump doesn't run dry. All you have to do to keep the sump from overflowing is making sure that you don't have more water than you can have in the tank up to the overflow line and the volume of your sump combined.

You've got it. Only thing to remember is to drill a small hole in your return line at the water level of the tank. Most return hoses/pipes hang about 3" down into the tank's water. If your pumps shuts off, this return line becomes a siphon, siphoning your tanks water back into the sump. The little hole in the return pipe at the water line in the tank breaks the siphon and keeps your carpet dry.

Gauge said:
I'm thinkin' about just buying one because I don't have a lot of room, and I'd just like to make sure that what I have works. Is there such a thing as too BIG of a sump for your tank?

Someone at one of the other forums is running an 80 gal sump on a 30 gal tank. I think it's silly but it doesn't hurt a thing at all. Having a large sump means having more water in your system, and a bigger marine system is a more stable marine system.
 
Okay, I was just wanting to make sure that it was okay. The reason I'd get a bigger sump is because I don't expect to have a 42 gallon tank forever. ;)

Thanks a bunch for the help. I'll try to remember the hole at the water line. That would have never ocurred to me.
 
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