CPR overflow question

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Yep... same design. The smoke will help keep algae down. The only difference might be cheaper materials, but not having seen either in person, the choice is up to you. Only negative part I see about that style is that air bubbles tend to gather at the top and can fail if you don't regularly keep the unit free of deterius and make sure to flush it out so there is no air.

You can also modify it with an air tubing release hooked up to a venturi valve of a PH... but that will come later. Let us know which one you choose!
 
I would have to buy a vacuum pump with either one. I don't know a hole lot about overflows (first sump/fuge) are the u-tubes better? I choose to go with these because there is no chance of siphon break because it has it's own pump. am I mistaken?
 
It has its own pump? :drinking: You sure? Those usually work off of gravity, where the water creates a siphon that pulls water down into your sump. What causes a siphon to break is air. If air is introduced into the siphon and isn't cleared out, it will break your siphon potently causing your tank to overflow.

U-tubes can also gather air pockets, but in my experience it is very not-often, especially if you have two u-tubes in one overflow for redundancy.

FYI, in a traditional sump/overflow box setup, the only pump that is needed is a return pump that can pump LESS than the overflow box can drain. No 2nd pump is needed to bring water down from your tank to your sump. (a pump for a skimmer might also be there, but again, that's a part of the skimmer assembly, not your general sump).
 
Ok i just wasn't sure becuse if you look at the marine depot site the under related items it has a vacuum pump and I assumed that went with the overflow box. if I wrong serves me right, you know what happens when you assume.
 
so does the cpr unit work without the pump? also I have a mag 7 return pump would a need a higher rated overflow box or should I get a lower rated return pump?

here are my specs:

Tank: 46 gal bow front

Lighting: Coralife aqualight 36" 2x96 compact strip light w/2 lunar lights

Protien Skimmer: Aqua C Remora w/ maxi-jet 1200

Heater: 2 150 watt

Filtration: Live rock (70-80 lbs including base rock) and live sand (3"-4")

Sump/Fuge: 20-30 gal
600 gph overflow box
Mag 7 return pump
 
The CPR overflows have a connection for an airline at the top of the siphon tube. This is attached to either an Aqualifter pump or to the venturi on a strong powerhead. The purpose of this is to remove air that gets into the siphon. This will work fine as long as your air removal mechanism doesn't fail...if it does and air is allowed into the siphon tube, it will build up in there until the siphon is broken and water will then hit the floor. While I have no personal experience with the Aqualifter pump, I have to wonder what kind of equipment you're getting for the price (less than $20, I think?). If I was going to go with a CPR design overflow, I would only use a Maxi Jet 1200 for air removal...they are notorious for running forever. One other thing you'll need to do is periodically clean or replace the airline. If it's exposed to light, algae will grow in there and clog it. My personal preference is a U tube overflow because: 1) They work 2) You eliminate one variable that could cause the siphon to break. JMHO.
 
Thanks for the advice. What do you think about the gph situation would a 600 gph overflow work with a 700 gph return pump?
 
You will need to calculate head pressure. A 700 gph pump will be able to pump around 500 gph or so 3' up into your tank... but it all depends on what kind of tubing you get, diameter, and how many angles you put into it. A ball valve on the exhaust end will do you wonders... just make sure you don't put it on the intake side.
 
so I am ok with what I am planning right. I don't mind making small adjustments I just want to make sure I have the right equipment
 
Rsquared333 said:
Thanks for the advice. What do you think about the gph situation would a 600 gph overflow work with a 700 gph return pump?

It should be fine as you are going to lose some flow due to head pressure, pipe friction, and fitting restrictions. A Mag 7 is rated at 480gph @ 4' and this doesn't take other restrictions into consideration. Here's a page on my site that will give you info on various pumps and their performance:
http://www.captiveraisedcorals.com/pumpspecs.htm
HTH.
 
500 or 600 is fine... it really depends on the diameter of tube that drains water down to the sump. A simple ball valve will help you out on the exhaust end of the pump.
 
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