# idea for overflow



## mastershake93 (Apr 4, 2010)

i have a cool idea for an overflow, i have a cpr backpack protien skimmer, and i was wondering that if i drilled a hole just under the origanal exit, and ran my plumming down to my sump whould work. i would have a slightly larger return pump to compensate for pumping up to my tank

-thanks


----------



## onefish2fish (Jul 22, 2008)

if the return pump burns out or fails the skimmer overflow your talking about will continue pumping flooding your floor.


----------



## mastershake93 (Apr 4, 2010)

i thought about that after i got off last night, and i am wondering if there is a way to make an auto shut off system or something. do you know of any?


----------



## AAHoudiniAA (Mar 13, 2010)

There has to be a way... I don't sleep because of this same issue running through my mind.
_Posted via Mobile Device_


----------



## onefish2fish (Jul 22, 2008)

there are plenty of ways. getting an overflow box, drilling the tank, using a reef ready tank

you may be able to rig some sort of float switch up, but i personally would NOT trust rigging anything. if you think about it, all the gadgets and things that it takes to get your overflow i personally think your better off drilling the tank. im a big fan of www.glass-holes.com


----------



## wake49 (Jul 2, 2008)

mastershake93 said:


> i have a cpr backpack protien skimmer, and i was wondering that if i drilled a hole just under the origanal exit, and ran my plumming down to my sump whould work. i would have a slightly larger return pump to compensate for pumping up to my tank


Your CPR backpack has an impeller that pulls the water out of the tank, right? If you don't match your return rate _exactly_ to your overflow rate, you will have a flood. And it will be impossible to do that, considering that a pump can lose or gain flow over the course of an hour/day/week...you get the idea. If your return pump is pumping at 600 gph and you have to compensate for 3' of head (say -50gph), then you would have to pump 550 gph _out_ of the tank. If you are pumping 525 out of the tank than over the course of an hour, you will pump 25 gallons more into the display in one hour. Imagine what will happen in five! Another scenario is you have matched the return to overflow perfectly. Then some algae gets caught in the impeller of the return pump, slowing down the flow to 500 gph. Now over the course of one hour, 50 gallons will be pumped out of the tank onto your floor.

The idea of that onefish is promoting is simple: gravity controls the overflow. Water is pumped into the display, and flows over a baffle and the drain is gravity fed. Therefore only water pumped into the display can flow over the baffle. If your return pump malfunctions, then water will stop being pumped into the tank and cannot flow over the baffles. 

With a drilled aquarium, you do not have to worry about a siphon break. That makes this the best option. If you have a power outage, water will stop being pumped into the aquarium (the reverse action of the return pump in a power outage will cause water to be siphoned the other way, so be careful of that) and no water can flow over the baffle. With a Siphoned Overflow when water flows over the baffle, it is then siphoned over the aquairum wall and flows down into the sump. When power goes out, that siphon is broken and needs to be restarted when the flow starts again. There are continuous models on the market, like the CPR CS series, which use an air-lifter pump to restart the siphon in the case of a power-outage. I have also seen DIY versions of this just surfing the net.


----------



## toddmc (Mar 31, 2010)

Oversizing your sump is safer than a float switch. By which I mean, figure out how much water your siphon will draw off before it breaks. So for instance, in a 12x30 tank with your inlet 2" underwater, it'll draw off 3.1 gallons. Add the water in your plumbing, and make sure you sump has that much extra capacity. Then if the pump fails, no flooding.

Make sure you go the other way too. What if the siphon breaks? How much water will the pump move before the sump level goes below the pump inlet, make sure your tank can hold that much extra water.


----------



## Castro235 (Mar 4, 2010)

mastershake93 said:


> i have a cool idea for an overflow, i have a cpr backpack protien skimmer, and i was wondering that if i drilled a hole just under the origanal exit, and ran my plumming down to my sump whould work. i would have a slightly larger return pump to compensate for pumping up to my tank
> 
> -thanks


There are some awesome pvc pipe overflow setups you can do, I just made a dual inlet overflow bla bla for around $20 for parts, I'm not sure of what the backpack skimmer is like, but basically as low as the water level in the tank can get from draining into the skimmer is where it will go in a power outage.


You would probably want a pump that is actually underpowered compared to how much the skimmer will allow the level to drop, if the pump is putting more water in the tank than the overflow can drain, you're just going to end up raising the level in the tank until it starts flooding.


That's the pvc overflow I just put together, you can use different size tubing, don't know how big your tank is, but I used 1" for my 55, you could maybe go smaller if you have a small tank, but i don't see it as being that big of an intrusion.
(the plumbing on the inside is not glued, but the outside is, that way I can adjust the piping inside of the tank, because it seems unclear even from tutorials whether I should have the lowermost part on the inside or outside of the tank)

I had thought about using a protein skimmer for an overflow box, but it just ended up seeming easier to build the whole thing from pvc and know everything would work right without a huge fight.


----------

