New lights, new problems: External overflows

[Gdbyrd]

I got my Nova extreme in today, 6X54w...LOVE IT. But my Octopus skimmer sticks up way too much for me to set the lights like they should be. Right now, almost 2 bulbs hang out over the front of the tank.

I think my only option is to get a small rubbermade sump and stick the skimmer under the tank. Since my tank is not drilled I will need an external overflow.

I have a HUGE question though. Most of these externals work off of a syphon. My power goes out in my house a lot..usually 20-30 minutes max. Let's say it goes out, overflow loses syphon..power comes on, pump then pushes up 20 or so gallons of water into an already full tank.

Is this the case? Anyway to get around this or are there any special overflows out there that this won't happen with?

 

[XxKnuckleheadxX]

the tank will drain down to where the water comes into the overflow. you would need to be more worried about it overflowing out of your sump. so what you do is a test mark a line on your sump then act like a power outage happend see how much your sump fills up. then that will tell you where your max water level should be.

 

[Bifferwine]

I used a CPR overflow box on my old 55 gallon tank, and you bought a little air pump separately (around $12 to $15 extra) that hooked up to the overflow box to restart the siphon when the power comes back on. That way the overflow box starts working immediately if the siphon is broken, with no chance of flooding.

 

[dcantucson]

+1 Knucklehead

Biff I don't understand your post:

"and you bought a little air pump separately (around $12 to $15 extra) that hooked up to the overflow box to restart the siphon when the power comes back on. That way the overflow box starts working immediately if the siphon is broken, with no chance of flooding"

Could you please explain further? Sorry, I'm s l o w tonight.

 

[Rcpilot]

Use an internal overflow like this:
Overflow Boxes - English

Drill the hole so the center of the hole is about 3 or 4 inches below the top rim of the tank. Install the bulkhead and silicone the overflow box in place.

When the power goes out, the water drains down until it falls below the teeth. Then it can't drain out anymore. Water goes below the teeth - it can't flow uphill. It stops running out of the tank and into the sump.

Thats why you run the sump about 1/2 full. When the power goes out, your tank flows until the water drops below the teeth. That fills the sump up. Mine stops about 2" from the top when the pumps are off.

When the power comes back on - the return pump starts pushing water back to the tank. The sump level goes down. The tank fills up until the water begins to overflow the teeth. Then the circuit is complete. Water overflows the teeth and drops to the sump. The return pump pushes it back into the tank.

Overflows happen when you put in a pump that will push MORE water into the tank than you can drain out of it. The bulk head is too small and can't flow out the water fast enough. So the pump fills the tank until the tank overflows.

It's easy to avoid this problem.

Oversize your bulkhead and plumbing by about 20% or 25%. Now as long as you stick to that size pump it can never pump the water into the tank as fast as the bulkhead will drain it. :Cheers:

Upsize the pump and you're screwed. It'll suck the sump dry and overflow the tank all over the living room floor.

 

[Bifferwine]

+1 Knucklehead

Biff I don't understand your post:

"and you bought a little air pump separately (around $12 to $15 extra) that hooked up to the overflow box to restart the siphon when the power comes back on. That way the overflow box starts working immediately if the siphon is broken, with no chance of flooding"

Could you please explain further? Sorry, I'm s l o w tonight.

If you buy a CPR brand overflow box, CPR tells you to buy a Tom's Aqua Lifter pump with it.

http://www.fishtanksdirect.com/ProductImages/aqualifterpump-small.jpg

It's a tiny little pump that is plugged in to the wall constantly, and is connected to the overflow box.

When the power goes out, the return pump stops returning water to your tank (duh), so the siphon is broken.

When the power comes back on, something needs to restart the siphon in the overflow box. The Aqua Lifter pump is plugged into it, and automatically restarts the siphon so your tank doesn't overflow in a power outage.

The Aqua Lifter pump will automatically restart the siphon if it's broken for any reason -- not just power outages. It just sits on top of the overflow box.

 

[dcantucson]

Thanks Biff. I sorta thought it was like that but wondered how the pump came on by itself to give it the lift. Duh, it just continuously runs.

 

[Bifferwine]

Yeah it's a teeny tiny little pump so you barely notice it's there.

 

[montoya]

I'm new to the overflow / sump setup. I just got my first one about two weeks ago. So far it has worked flawlessly in terms of the siphon. If I understand correctly - in most cases the siphon in the overflow will not break during a power outage - correct? I have powered down my tank several times the past couple weeks while I clean, do water changes, etc. Sometimes for an hour or more. In all cases the overflow tube has kept its siphon and simply started back up when I powered up the tank again. Regardless Biff's pump suggestion seems like cheap insurance. I think I will pick one up. I have also seen a small pump used to vent air out of the top of the overflow tube that accumulates over time? Does anyone have this setup? Could I also just drill and mount a tiny valve of some type at the top of the "U" to manually vent air out on occassion?

 

[Gdbyrd]

I have 4 and 3/4" behind my tank. Does anyone know of an external overflow that'll fit behind it? I called Dr. Fosters and they are looking into an Eshopps model to see if it'll fit..But for right now I can't find anything :*(

My lights are completely covered in salt! I'm really tempted to pull my skimmer off now and start doing twice weekly water changes. I only have two fish in my tank so the bioload should be really small.

If worst comes to worst..couldn't I use a small overflow? Like a 300gph(I saw one that was 4.5" behind tank).

 

[Rcpilot]

Drain the tank 1/2 way. Slap a big piece of plastic on top of the water and tape it to the side of the tank all around with masking tape. Drill the back with a 60mm hole saw and drop a 1.5" bulkhead in there. Glue a very short piece of straight PVC tubing into the back of the bulk head and then shoot a 90 straight down or off to the side - depends on the layout of the plumbing. Then put a shut off valve on it and shut it to the OFF position. Use a big ball valve. Take the plastic out of the tank and clean all the tape off. Silicone an overflow in there from Bulk Reef Supply. Tape it in place to hold it from slipping. Give it 24hrs to cure. Fill the tank up. Plumb the sump.

The fish will be fine for 24hrs with a couple powerheads. Your worst problem will be making sure the tape sticks to the overflow so it doesn't slide down the side of the tank before the silicone dries.

DO IT!!!! :mrgreen: :Cheers:

 

[Gdbyrd]

What happens if while I'm drilling it I crack the tank? Lol.

That'd be a wonderful solution but I really do not feel comfortable enough drilling a nearly full tank.

I sent an email to MarineDepot asking about an overflow that'll fit back there..also called Dr. Fosters. Just going to have to wait on them.

Is there any reason I couldn't use a 300gph overflow? Something>Nothing right?

Edit: RC, I just read the PM. Most of those Eshopps require only 3" of space behind the tank! Woohoo. Now, what gph do I go with? I only have a 8g sump to work with : /

 

[Rcpilot]

I was scared shitless the first time I drilled a tank. Piece of cake. I'm REALLY tempted to drill my 30H while it's 1/2 full. -Pirate- I want to put a 15g sump under it.

But I won't hassle you because I know it's risky and I probably wouldn't do it in your shoes - 'cept for I know I can do it now. It's friggin' EASY.

On the GPH question - what size tank are we talking about? The sump is 8g - what size is the tank?

 

[yote]

Garret,Go with the highest GPH overflow you can get back there.You want it to handle more flow than your actually going to put through it.That way you dont have to worry about your return pump keeping up with it.

 

[Gdbyrd]

Tank is a 55g. I'm looking seriously at a 1000gph overflow. The stand is just too small to get anything larger than that 8g down there without some serious acylic work.

 

[Gdbyrd]

Well, I did it. I ordered a 1000 gph external overflow, a 1300 gph pump, an in sump skimmer...

And for my 2x frag tank :) I ordered 2x 65w PC, 350gph pump.(going skimmerless and sucking it up on the water changes).

All together...I might jsut be sleeping on the couch tonight. But when all my stuff gets in, I'll be happy and it'll be worth it!

I just wish I had had more days off this week so I could have gotten further along on my frag tanks. It's too damn cold to paint the backs of the tanks tonight : / I need plumbing too!