Small DIY Refugium Help

I'm thinking of building a refugium out of one of those small 2.5 gallon tanks that they sell at PetsMart. I have a 29g tank now that does not have a sump and there isn't any room in my stand for one. Currently I use canister filter and a HOB AquaC skimmer. I can't quite get my nitrates to drop to 0, they always hang around 10-20ppm so I think this would help get them down.

The problem is I can't figure out how I would go about feeding water into the fuge from my display. I don't want to pump it because I'm afraid of what may happen if that pump got ahead of the return. Also I don't want to have to buy 2 pumps. I thought about an overflow, but even the smallest rated one I see out there look they will feed too much water into the refugium causing another flood.

I was thinking siphoning the water with just inline tubing into the fuge. Much like what you would do when drip acclimating except I'd leave the tube unrestricted. Have one baffle there even though I don't think this will cause many bubbles. The middle would be all macro. Then one more baffle and a small return area with a pump. The return plumping would most likely be PVC. Right now I'm just brainstorming and I can't find much information on anyone else doing it this way so any input you guys have would be appreciated.

 

I know the CPR HOB Refuge returns the water VIA Gravity, so you would not need 2 pumps.

 

Yeah I looked at those and it appears that I do not have enough room behind my tank for it to fit. I also looked into building a 10g sump/fuge combo and that wouldn't fit inside the stand cabinet. I kinda backed myself into a corner and now I trying to find a solution. I was thinking about hanging a breeder box inside of the display tank with cheato in it as another idea.

 

I think it would be impossible to get the airline tubing syphon and return pump to match up. I would go with a small HOB overflow box. Drilling the DT would be best, but I guess that's out of the question.

 

The smallest overflow box I can find out there is the one made by eshopps. It's rated for up to a 75 gallon tank. I'm afraid that's going put too much water into the small little 2.5g tank. Is there a way to restrict the flow somehow from the overflow box?

 

i think you should search turf algae scrubber. You can make one for pretty cheap but i would still do a small overflow. Alot of people rave about these DIY nitrate/phosphate annihilators that you can build in a small bucket. As for water movement you can have a good bit of control over your flow thorugh your fuge/sump/scrubber through plumbing. Having a ball valve/ gate valve on the return would control the amount of water flowing though your overflow. Using check valves, aqua lifters to keep suction, and air gaps on the returns pretty much takes flooding out of the equation.

 

The overflow box will only drain what the return pump pumps back up to the DT. Although if the flow is too little the U-tube may collect bubbles and break syphon.

 

You only need like 5" of space between the back of the tank and a wall to fit a HOB fuge. Can't you just move your tank a little?

 

I'm at 4.5 inches. It would be a tight fit. I supposed if emptied most of the water and had the help of a friend I could try. With the water I'd say it would be impossible. Even empty I have a lot of rock and sensitive livestock I also don't know if the stand could take that weight being pushed. I could be wrong though. I've never tried to move something like that before.

 

If you give me dimensions you need, I can work on making a small overflow box for you. I'd just charge you for the materials and shipping.
I know about 4" front to back, how tall do you need?