Upstream refugium(s)

[bprinehart]

I'm in the final planning stages of my prop system. So far what I'm planning on doing is using the 33 L as the growout tank, circulation will be provided by an over the back closed loop manifold, 40 L for the refugium, and a 20 L for the sump. The area that I have available to use is the old workshop area of the house, in a back corner of the basement. A very sturdy 12' x 3' x 2" thick oak slab, reinforced with what looks to be sheet metal under the oak top. The legs/frame are made from 2"x2" x1/4" hollow core metal of some type, I'm assuming steel, so this thing is sturdy to say the least. The oak slab is bolted to the frame, and the legs are lagged into the concrete.

 

There is no shelf underneath, and I do not feel like drilling any holes into the slab. Given the options available to me, I've decided that I will do an upstream refugium and letting it gravity feed back down into the main tank The main purpose of the refugium will be to house a DSB, and possibly some chaeto for NNR, maybe some pod production. I plan on raising the top of the refugium up via a solid wood shelf approximately 2 inches taller than the height of the top of the growout tank. The growout tank, in turn be will situated approximately 2 inches taller than the sump tank, which will house the skimmer, and heater, and any other stuff, and gravity feed into it. So in a nutshell, my refugium will be situated 4 inches taller than the sump.

 

Aesthetics are not really a concern here, as this will be strictly for growout, and my own personal amusement. The circulation as stated earlier will be provided by the closed loop manifold, so I do not need a super high flow return pump, and from what I understand, I do not necessarily want a ton of flow through the refugium to allow for maximum contact time with the DSB. My main concern is getting the water from the sump up to the fuge. I'm thinking that at a head height of only 4 inches, I should be able to use a Powerhead, like say a maxijet 1200 I also have a 900 available or even smaller to keep the loop going. For the plumbing I was considering 1/2" bulkheads, which if I remember correctly should be around 300 GPH. The head loss calculator over at RC approximates I should get approximately 247gph from a MJ 1200 at 1 ft horizontal length, 4 inches vertical height.

 

Anyone see any issues with that? Keep in mind that this is all equipment I have on hand and planned for use, so I am really not looking to go out and purchase yet another pump. Monster flow is not the goal here, just a nice sustainable slow flow from the sump back up to the 'fuge.

 

Thanks,

 

Brian

Edited November 13, 2007 by bprinehart

[Grav]

I'm worried about the 1/2 bulkhead allowing water back to the sump.

 

Would be fine as a drain line from a main tank to a sump str8 down or close to that but I would not expect it to drain 300 gph with only a 4 inch drop and 1 foot horizontal.

[lancer99]

Agreed with grav...the flow through a given size bulkhead is dependent on the head above it, or in your case, the drop from it. If the vertical distance from the bulkhead in the fuge to the water level in the main tank is only 2" (and my 4 a.m. math is correct), you will need a 1" bulkhead to get close to 300 gph into the main tank.

 

And I would use a larger bulkhead from the main tank to the sump, just for safety.

 

-R

[bprinehart]

Agreed with grav...the flow through a given size bulkhead is dependent on the head above it, or in your case, the drop from it. If the vertical distance from the bulkhead in the fuge to the water level in the main tank is only 2" (and my 4 a.m. math is correct), you will need a 1" bulkhead to get close to 300 gph into the main tank.

 

And I would use a larger bulkhead from the main tank to the sump, just for safety.

 

-R

 

This is why I ask these questions. I would have ended up with a puddle of water on the floor! Good 4am math btw. So, if I were to have a 1 inch bulkhead in the main tank, draining into the sump. Do you think the 1/2" bulkhead from the 'fuge to the main tank would be enough? Or should I go 1" from there as well?

 

Thanks for the help.

 

Brian

[Almon]

I have a setup almost exactly as you described. See this post #13 of this thread.

 

A normal U-tube for an overflow works great to move water from the refugium (left tank) to the frag (bottom) tank and supports 300 gph. However, there is very little space between tube ends, so you need to get the tanks very close together. What works best for me is to have an external aquaclear filterbox, motor NOT running, on my frag tank (bottom tank) and the U-Tube in it coming from a homemade internal overflow box in the refugium (left tank). The tanks have a 4" height different, but there is 2" difference from the level in the refugium and the level in the aquaclear external filterbox.

 

The 55g fish (top) tank is only 2" above the refugium (left tank) and I did not have enough difference in height to use the aquaclear external filterbox, so I am using two homemade U(like)-Tubes which are deficient and needs to be checked every few days. I really need to raise the right tank up another 2" and use the aquaclear external overflow box. That method is flawless.....works perfectly.

 

The bottom overflow returns water back to the sump which is 8' away and a 1" drain to the sump is just barely sufficient.

 

Edited November 30, 2007 by Almon

[lancer99]

Brian,

My 4 a.m. math (no time to check it!) says you'll only get ~73 gph through a 1/2" bulkhead, ~292 gph through a 1" with 2" of drop.

 

I meant to say that the bulkhead from the main tank to the sump should be larger than the one from the fuge to the main tank. If they are the same diameter, and you're at the max flow rate, if for any reason the flow to the sump is slightly less (unequal growth of biofilm, etc.), you'll eventually end up with water on the floor.

 

Here is the formula if you want to check my work:

 

http://reefscapes.net/articles/breefcase/fluid_dynamics.html

 

-R

Disclaimer: Fluid dynamics and math are a long way from being my field of expertise!