Overflow Size for Big Tank

[Inkedsphynx]

I tried this in another forum and haven't gotten any response, so I figured I'd try it here.

I'm very new to the hobby, and I'm trying to find information on a few subjects that just don't seem to be well covered in anything I've read so far.

I'm going to be ordering a 72x24x31 240G tank, and I'm attempting to determine what I want to do with overflows (These will be pre-drilled and constructed with the tank from where I'm ordering). I was thinking that it'd be good to get one in each back corner. My concern is, how much area do they need to cover? How big should the drain/return holes be in the bottom?

I understand that there are many issues to a question such as this, including the desired flow rate of the tank. My problem there is that I am not sure how to determine what amount of turnover/flow I need.

I will want to do corals in the tank, though I've not given thought to what kind yet. Right now I'm just trying to soak up information, and get a plan together for the actual setup itself. Then, once I get that all taken care of, I figure it'll give me time to properly cycle the tank while I learn all I can on livestock and decide what I want to go with.

(And naturally adjust the setup to work well with the life I place inside the system)

So if anyone could offer tips, information, or direct me to online or offline information addressing these topics, I would *REALLY* appreciate it.

Thanks!

 

[X-FACTOR]

(2) 1 1/2 outs and (2) 1 inch return's minimum, 18 inch's of overflow per side.

 

[chucksta1]

With the thought of "how much flow do I need", it also a matter of where the flow (in the tank), is coming from. The term "turn over" in the tank is related to flow in the tank, regardless of source. If the source of flow is back from the sump, the total flow is limited to the ammount of water that flows into it as that is what would be called an "open loop" . The return pump must do all the work of returning the water to the tank, with loss for " head pressure" and bends and restrictions in the return. A "closed loop" charges the water into the pump and there is virtually no head loss. If you run a lot of flow through in tank pumps, the flow through the sump needs to be enough for what goes on in the sump only, as the main job of flow goes on inside the tank itself.

Any energy used to move water requires energy, which costs money (electrical) to provide and adds a heat load to the system. If you're going to run an open or closed loop system and metal halide lighting, you may need a chiller, or be prepared to put a fan over the sump, vent it and go through three to five gallons a day of R/O for evaporative cooling.

Personally, I do my in tank turn over with high efficency power heads (Tunze streams) , my flow through the sump is less than 200 GPH. but my turn over in the tank is over 1000 GPH (on low setting). I have 1000 watts of light (MH & actinic) and I don't have a chiller.

The post above this is right on about the sizes of the overflows. You can always under use what you have, but addiing more can be a problem.

I had an Iwaki 40 running my returns, but it added too much heat load. Now I have a POS needle wheel pump returning to the tank and let the power heads control the flow in the tank. You don't seem sure what you want in the tank. I'd suggest that you'll never go wrong to over engineer from the start and leave your options open for the future. SPS corals love a clean tank and a lot of flow. Softies don't want to get blown atound the tank. Try and design for flexability and economical performance.


31 tall? hope you're over six five or have a small child to help aquascape. I'm 5.8 and need a chair to reach the bottom.

good luck ,

Chuck.

 

[Inkedsphynx]

Thank you very much for the replies, that is quite helpful!

I haven't planned out what I want to do coral wise yet, as I'm still learning about which corals are which, and what they all like, but I agree that it'd be better to leave myself flex room to start with.

I originally didn't realize that you could use a closed loop (of course it took me a few days to figure out what the hell it was, as far as marine tanks go) to increase turnover in the tank without actually running additional water through the sump. That makes things much easier, especially since if need be, I can always build a new closed loop to match what I want to do in the tank.

With that in mind, could someone give me a rough idea regarding turnover amounts that various types of corals like?

Oh, and I'm not quite 6'5", but I don't mind pulling out a stool or chair to get into the tank. I really like the extra height though, as it gives you more front viewing angle, so you can see everything better. Now if only I could afford to go another 6 inches wide, then I'd be truly happy!

 

[X-FACTOR]

A basic rule it to turn over a reef tank 10 times an hour...Just a guideline My 300 is almost double that.