using CPR overflow box w/out device

[treesprite]

Why does the CPR continuous siphon overflow box need to have a siphoning device anyway? I saw that some people use homemade CPR-type boxes without using any aqualifter or powerhead for suction. As long as no air gets into the U part, the siphon will not be lost just like with using U tubes.

 

I took off the Aqualifter, attatched a 3-way valve to teh end of the airline that is attatched to the CPR overflow box, suctioned out the air by mouth from one of the prongs of the valve, turned the valve off so no air could go back in, and there is no problem. The siphon keeps going and the flow rate is much higher than even when my Aqualifter was new, so I can allow more flow into the tank from my (relatively) powerful return pump. I turned teh pump off, waited a few minutes, turned it back on and the siphon started right back up on it's own. I turned the pump off and am waiting a couple hours this time to see if any air gets in that will keep the siphon from starting right back up - if the siphon holds I think I will just use the box like this without any Aqualifter or powerhead for suction.

[extreme_tooth_decay]

Why does the CPR continuous siphon overflow box need to have a siphoning device anyway? I saw that some people use homemade CPR-type boxes without using any aqualifter or powerhead for suction. As long as no air gets into the U part, the siphon will not be lost just like with using U tubes.

 

I took off the Aqualifter, attatched a 3-way valve to teh end of the airline that is attatched to the CPR overflow box, suctioned out the air by mouth from one of the prongs of the valve, turned the valve off so no air could go back in, and there is no problem. The siphon keeps going and the flow rate is much higher than even when my Aqualifter was new, so I can allow more flow into the tank from my (relatively) powerful return pump. I turned teh pump off, waited a few minutes, turned it back on and the siphon started right back up on it's own. I turned the pump off and am waiting a couple hours this time to see if any air gets in that will keep the siphon from starting right back up - if the siphon holds I think I will just use the box like this without any Aqualifter or powerhead for suction.

 

Air tends to accumulate in there. Sometimes it is very slow, other times it is not. If you have no air getting in it, you do not need anything to suck it out. You should test it over at least a week to see if air accumulates in there, though.

 

I have used CPR overflows for years, and love them. I never had a leak or loss of siphon. In all my experiences, air does accumulate over time without a suction device.

 

tim

[fishcam]

Air tends to accumulate in there. Sometimes it is very slow, other times it is not. If you have no air getting in it, you do not need anything to suck it out. You should test it over at least a week to see if air accumulates in there, though.

 

I have used CPR overflows for years, and love them. I never had a leak or loss of siphon. In all my experiences, air does accumulate over time without a suction device.

 

tim

 

+1 I have two of the 100 (large) models, and run two aqualifters on a timer 4 times a day for ~5 mins.

 

Air does get in... IME way more than a simple U tube style, but I guess that depends on how many bubbles you're in-tank portion is generating. Def required, I think.

[Origami]

Air tends to accumulate in there. Sometimes it is very slow, other times it is not. If you have no air getting in it, you do not need anything to suck it out. You should test it over at least a week to see if air accumulates in there, though.

 

I have used CPR overflows for years, and love them. I never had a leak or loss of siphon. In all my experiences, air does accumulate over time without a suction device.

 

tim

 

+1 as well.

 

The CPR's "u-tube" section has a bigger cross section than a standard u-tube. Thus, the water velocity is lower in the CPR than in the standard u-tube. Air tends to be swept up and out in the standard u-tube configuration but, because of the reduced flow, tends bo be susceptible to accumulation in the analagous part in the CPR design. This accumulation must be removed as air in the tube has the potential to reduce or even entirely stop flow.

[treesprite]

14 hours later I turned the pump back on and the siphon picked right up where it left off, so no substantial amount of air got in there. So no I guess I need to see how long it siphons without so much air getting in it that the siphon gets disrupted.

 

I have been thinking about converting the 2 overflow boxes to use U tubes so I don't have to worry about suction devices anymore, trying to simplify things. If I can get the boxes to work without non-stop use of devices then I won't feel like I need to do it.

 

+1 I have two of the 100 (large) models, and run two aqualifters on a timer 4 times a day for ~5 mins.

I've never heard of anyone doing this. How did you come up with the idea for this, at this particular rate of use? It certainly helps to extend the life of the Aqualifter if it works being used this way.

[treesprite]

So far the large CPR overflow box is not seeming to collect air, BUT I tried this with my smaller box and it DOES collect quite a bit of air over a day's time, though it ran for a couple of days before I decided to connect it back (to a powerhead - I have 2 Aqualifters and both are working too slow even though I see no clogs).

[sam75]

You can actually take the aqualifter diaphragm apart and clean or repair the the mechanism (they sell replacements for a few bucks as well, but times are tight). I always thought it would break the pump if you took the diaphragm apart, but it doesn't. In my case one of the tiny flaps inside had become dislodged over time (3yrs old), I was able to super glue it back in place and it worked like new again.

 

(also +1 on using a pump with the CPR - I've also heard of some people hooking the siphon line to their return pump, but I've never tried it)

 

-S

 

(I have 2 Aqualifters and both are working too slow even though I see no clogs).

[treesprite]

I was going to take one apart a while back (done it before) but the screws are way too tight, I can't do it. These Aqualifters are not that old. Powerheads work fine as long as stuff doesn't get caught int he powerhead and clog its intake slowing down the rate. Gotta have a powerhead in the tank anyway so may as well stick an airline in it (goes in teh venturi hole, other end on the ofb)