Overflow Question??

[Calvin]

Okay, so I've decided to go reef rather than fish only. I would like to put a wet/ dry filter/ sump/ protein skimmer below the tank. The problem is, I've only got a two inch clearance behind the tank. Just enough room for the Fluval (304) hoses to fit. I'd like to add an over flow to feed a sump but the room just isnt there. I'm not terrible excited about the prospect of draining and lugging the tank out a couple inches. My question is, Is there a way to supply the sump with water besides going with the overflow? Is it possible to siphon directly from the tank to the sump using a ball valve to control flow? I imagine that I could fabricate a half an overflow in the tank and have a sump large enough to handle the excess in case the return pump failed. Any help or suggestions would be greatly appreciated.l

Thanks in advance,
Calvin

 

[justDIY]

how about using a siphon box overflow off the side of your tank, rather than the back?

either that, or drain that tank down and budge it out a few more inches!

you cannot siphon water out one tank into another without controlling the air pressure in one of the two tanks... without controlling the air pressure, the siphon will operate unpredictablly, even if you put a valve on it.

example:

you start a siphon to supply your sump, and you adjust a valve so that the return pump appears to be pumping water out as fast as it's coming in....

scenario a> your siphon is actually running a hair slower than the pump, and the pump drains your sump at 3:45AM and you are awoken to awful noise of pump running dry, or it has run dry and burned out, or shut down and will restart when it cools off.

scenario b> your siphon is actually running a hair faster than the pump, and while you're stuck in a traffic jam after work, your sump has overflowed and is draining your tank onto the floor.

scenario c> you build a sump large enough to handle enough water from the tank to break the siphon ... but now your return pump will dutifully return all that water, plus the water in the sump itself to the tank, and then procede to run dry as the siphon is broken and can no longer drain the tank

none of these are very good! so I'd recommend using a side of your tank for the overflow, or moving it off the wall some more... maybe some applicance moving equipment would be of assitance

HTH

 

[loganj]

I agree 100%. Not using an overflow is not an option.

 

[Calvin]

Is it possible to fabricate am elongated overflow box? One that is longer rather then wider? If not, looks like I'm moving the tank this weekend.

 

[loganj]

You can make the overflow any size you want to, but... (Why does there always have to be a "but"?!) What you're going to run into is having enough clearance to install the drain pipes in the bottom of the external box. If you have 2" of clearance, then you'll be limited to a box that's about 1 3/4" front to back. Figure the acrylic is at least 1/4" so you've lost another 1/2" due to the front and back walls of the box. That only leaves you with 1 1/4" to install the drains. I don't think you could wedge anything more than a 3/4" fitting in there. Possible you could use two 3/4" drains and have the siphon tube come in between them. I think this will really limit the flow rating of the overflow though. It'll be really hard to get in there to tighten the fittings no matter what size they are as well. My advice is to scoot the tank out so you can use a larger external box.

 

[Calvin]

Thank you for your advice. You bring up many points I hadnt considered. Your help has probabaly saved my tank and carpet.

 

[AndySmithers]

Calvin,
I had the same problem as you - only 2" of clearance, needed around 3 1/2" minimum for the Lifereef slimline overflow.

Solution? Simply move the tank out a couple inches.
Again my tank is 90 gallon, like yours, weight about a zillion tons when full!, but a long piece of 2x4 as a lever along with a piece of smooth wood to prevent gouging the wall with the lever and VERY CAREFULLY inching it out allowing the frame to settle before inching further..... and it worked fine!!!
My stand is on hardwood floor, might not be so easy on carpet but I'd definitely give it a try if it were mine...

Andy.

 

[ReefLady]

I agree 100%. Not using an overflow is not an option.

True, if the holes are drilled in the bottom of the tank. However, our current tank is our 8th reef tank in the last 13-14 years, and we've never once used overflows. Our tank is a 180g, which is plumbed to a basement sump/refugium/prop tank.

The tank is drilled w/3 bulkheads (no overflows) - holes sit at about 4" from the tank's surface. If the power fails, all the water that could potentially drain from the tank can be held in the sump.

Pics of our setup here: http://home.comcast.net/~76fxe/sump.htm

FWIW, I would not use a wet dry if you're considering a reef tank. Protein skimmer, LR, DSB should be your total filtration "package".

HTH,

 

[Guest]

Teri,

Can you elaborate on how you equalize the flow in your tank to keep the water above the bulkheads? They seem to be a lot lower than the water line....

A little confusing to me, because you are not using a closed loop system.

 

[loganj]

Very true Teri...I didn't mention drilling the tank as I didn't think it would be a viable option in this case. I have used tanks drilled like yours and they do work very well.
I agree on the wet/dry as well. They are really best suited for FO tanks where there is no other solution for biofiltration.

 

[ReefLady]

timbo2,

The only fundamental piece of logic that needs to work with this system is that your drain capacity must be equal to or greater than (hopefully greater than) your return pump volume capacity. This way, you can never pump more water into the display than can drain out (no overflowing).

The holes are drilled (on cernter) about 4" below the water's surface, however, the strainers are angled up so that the actual water surface never goes below the strainer, which are positioned about 1" from the surface.

Our (100g) sump is kept at a level low enough so that when the return pump is turned off, all the water than drains out of the tank can be held by the sump.

Logan - I knew you didn't mention drilling for that very reason - I would suspect that the issue of moving the tank would be minimal compared to drilling it.

HTH!

 

[Guest]

Thank you. I did not notice the 1" below the surface thing....

 

[blancoh2o]

Must be nice to have a basement for all your equipment. Most of us don't have that luxury. You have every right to show off your system.