over the tank refugium help please

[krux]

I am adding a 8 gallon rubbermaid refugium to my 30 gallon tank as an experiment so i can get the technique down when i get a 110 in a couple months.
My current problem is choice of powerhead to get the water out of the tank (not drilled, no overflow as i have no sump) and up the 2-3 feet to where my refugium will be placed.
I have read the formula for figuring head pressure and what not, but as i do not have an extensive background on pumps and plumming, those numbers just arent helping. Hopefully someone can make a suggestion?
At the LFS they only carry Rio Powerheads, which I am lead to believe from posts here add significant heat to your tank. At any rate, they suggested a rio 1100, running about 35 bucks, that uses an ID 5/8" flexible line to move water. Bulkheads are available in this size.
Will this rio work, that is, pumping enough water through a 5/8" ID flexible tube 2-3 feet vertically, or do i need a bigger powerhead? Can i get by with a smaller powerhead, maybe from a different company? Is 5/8 a large enough line, or so i need to find a powerhead that connects to a 3/4 inch line?
Also, inside the refugium i was planning on placing a Rio 50 or equivalent, a 60 gph unit, to simply move the water around so the macro-algae has some movement.... is there another brand, or a different size powerhead for inside the refugium that would work better for this purpose? one selling feature of the rio is the directional attatchments, but i assume they will fit on any powerhead with the same size outflow pipe.
Finally, Do i need to use a larger than 5/8 return line to insure that the refugium will not overflow? haven't located any concrete information on this, but it seems like a good idea since the return is gravity fed, via a return hole lower than the inflow hole. assuming 5/8 would a 3/4 inch return line be sufficient, or do i need to go to 1 inch?
Again thanks for any input.... not looking for anyone to crunch numbers for me, just hoping maybe someone has a similar set up, or has done the figuring to make one themselves. Also past expieriences with different makes of powerhead would be great.
Ryan

 

[oceanjumper]

Ryan,
Looks to me your understanding is okay. Though, in your situation I would get now a larger pump. Even an exterior pump preferably. Personally, I want as little equipment in my display tank as possible. And if you later upgrade you can use the same larger rio (or Mag, or CAP)
If you just want to feed the fuge, a small rio will do. The magic number (as calculated/determined by Bang Guy) is 8x turnover. If you have a 8 gallon rubbermaid, you probably will fill it with ~6 gallons. As such, for now you just need 8x8 = 64 gph flow. That would be (closest) accomplished with a Rio 400 at 3 ft. (provides 57 gph at 3 ft., 100 gph at 2 ft.). How do I get this? See this link:
Rio Pumps Table
By the way, note the recommended Outer Diameter (OD) measurements of the return lines. With the Rio 400 this would be 1/2"
SO, with a Rio 400 you don't have to do anything else. If you would chose a larger pump (as I would do), you need the "bleed" the excess flow back into your tank. You don't want so much current in your refuge that in no time all the stuff is "blown" into your display. The bleeding part can be arranged by making a T in the return line, feeding it back to your display, controlled by a ball valve.
Well, even if you did not want me to do the numbers, it is important you understand them. If we do the calculation with a RIo 1100 at 3 ft., you get a 296 gph flow. About 3 x too much, so you will need to make the T for the bleeding part.
As far a overflows in your refuge. I would get one 1". You can buy these online and your LFS might carry them. I got mine from here
Look at my website under "equipment" of the stuff I bought to setup my refuge. Besides the tank, lamp, and 1" bulkhead, I got all the stuff from Home Depot.
Good luck

 

[oceanjumper]

Originally posted by OceanJumper
If you have a 8 gallon rubbermaid, you probably will fill it with ~6 gallons. As such, for now you just need 8x8 = 64 gph flow.

Ooops! Little mistake. Of course this should have been 8x6 (six gallons!) not 8. Ah well, you can do now the new numbers yourself...

 

[krux]

I saw in your setup the t valve, but as far as bleeding, im not quite sure on what that involves.
Purchased today a 3/4 inch bulkhead, "L" thread to male flange, a tube clamp, and 4 feet of 3/4 inch tubing for 18 dollars. The fellow at the plumbing supply place said that a 1" return would work fine, especially if i put a ball valve into the inflow line somewhere for finer control of flow. This seems in line with what rio suggests.
Is there an alternate brand to rio that i should look into, for durability, noise, and energy effeciency?
Might an overflow, dropping down and to the side of the tank to an approximately even level with the display, creating a sort of sump in perhapse a 10 gallon tank, then allow me for more flexibility, as far as a water pump, instead of a powerhead goes? The pump height would increase approximately a foot vertically, but it would allow me to move the pump out of the tank, and i suppose i could then split off of that later for a calcium reactor or some such. Given this scenario, a small sump, designed at this point explicitly for a place to house a pump to send water to the refugium, are there any suggestions for a pump that might serve me better than one from the rio line? Is there any merit to buying a larger that needed pump and controling the flow with a ball valve, or will that just unnecessarily shorthen the life of the pump?
Thanks for your help thus far oceanjumper!
Oh also, why do the recommend tubing based on outside diameter? wouldnt that make the inside diameter vary wildly, dependant on the thickness of the tubing material? a 3/4" od tubing with 1/16" thick walls, would not fit the same flange as one with 1/8" wall thickness... This is especially important when buying bulkheads..... if the output on the rio fits an ID 5/8 inch line, can i safely buy a 3/4" bulkhead as they suggest, and the same line will fit at both ends, or do i need to buy an increaser?
I can see why people use threaded pvc fittings, a little bit more universallity.