CPR overflow unit

Ok, I just my CPR overflow unit today with my 6 feet of 1" tubing. I can't seem to figure out how the tubing connects to the unit. Do I need an adapter of some sorts? :confused:

mr . salty

Active Member
The overflow should have one or more tubes out of the bottom of the outside box that the plumbing is attached to.
I am already not liking this CPR overflow unit. 1" tubing obviously doesn't fit and CPR told me I either have to hard plumb it or buy 1 1/4" tubing and buy an adapter. I've never done any plumbing before in my life. Do they make every type of bend in PVC so I can easily get the water from the overflow box to the sump? It's obviously not a straight line.

the new guy

You can find plumbing at any hardware store and in any bend you need. Just a suggestion, they sell PVC that is threaded so if you have never done any plumbing all you have to do with this stuff is screw it together with some Teflon tape on the threads.
[ April 16, 2001: Message edited by: The New Guy ]
Ok, mission failed. Went to home depot and they didn't have crap when it came to 1" PVC. They had plenty of choices for 1 1/2" or 2" but all they had were 45 degree bends that weren't even threaded. Gonna have to check out a different store i think.
Can somebody with the CS90 overflow unit or similiar tell me how they hooked up theirs? What is the white tubing called that goes from the built-in overflow in my display tank to the sump? It's flexible and looks easy to use. Sorry i'm not very technical when it comes to stuff like this. Could I buy a similiar hose/tubing for the CPR overflow unit?


Hi SaltwaterKid,
I use two CPR sumps, but you are throwing me off with your overflow box question. Are you having difficulty getting the hose to run from the prefilter to the skimmer section of the sump? OR, are you having problems getting the hose from the filter to the return? Let me know, maybe we can walk you through this.
Don't worry, I'm confusing myself too. I have the CS90 unit which claims to have a 1" bulkhead attached to it. I am having problems connecting 1" tubing to the bulkhead. The tubing is my drain line which will go into my display tanks sump. Make more sense?

mr . salty

Active Member
Exactly what is this dificulty you are having??? Is the 1" tube not big enough to fit over the fitting on the bottom of the overflow?? What is the measurement of the outside diameter of this fitting?? Could you just use a bigger hose that would fit over this fitting???


New Member
When you go to Home Depot or Lowe's look in the flexible tubing section, not the pvc section, they are usually just one isle over. But they should have just about any bend you could want not to mention reduction connections. If that doesn't help try a pool supply store. Hope this can be of help.
Come on guys, if I told you everything then it wouldn't be any fun. :) Basically the 1" tubing i bought is about the same diameter of the inside of the bulkhead. To be honest, 1" tubing was the biggest I found. It's so much easier when you are looking at the part than trying to describe it through words. The outside diameter of the bulkhead is 1.5". The inside diameter is 1". The inside is not threaded but the outside is. What are my options?


forget how it works but take the pipe and use pvc to glue in the cpr then glue a female then use the piece for the flex. its simple just take it to HD. = The inside is 1"id use 1"pvc, glue. with pvc solvent. then glue a piece of pvc into a coupler to what you just did then to the 1" female. Get a threaded 1" male (adapter for flex pipe)tape it screw it in then connect 1" flex tupe and clamp. One way to do it. Theres many ways

mr . salty

Active Member
Yeah,If the id of the bulkhead is 1',Then a two inch long piece of 1"od pvc should be glued in to the bulkhead.Then your 1" hose will slide over this piece you glued in place.Then clamp it and your in buisness.
Ok, i was finally able to take time and find all the parts I needed for the overflow unit. I currently have it all setup and its working perfectly. I have a powerhead inside the refugium that has a small tubing connected from the venturi valve to the top of the overflow unit. This was the only way I could keep the siphon going. My question is, what cautionary meaures can I take to make sure the refugium doesn't overflow and that the main tanks sump doesn't overflow. I noticed two things. If I turn off the supply line powerhead that is feeding the water into the refugium, the siphon reverses and it sucks water from the refugium into the sump. It came pretty close to overflowing the sump. The other thing I noticed was that if I remove the venturi line from the overflow unit the siphon stops and the refugium continues to fill up until the water would eventually overflow over the top and onto my floor. Are there any devices besides a UPS kit that I can buy to prevent a major disaster?


I had to struggle with my cs90 when I bought it. Its has been up and running for 7 months now without major problems.
You can do things to prevent the reverse siphon. You can put a plastic reverse check valve (i got mine from home depot) in the pipe that is going up to the tank. You can also cut the pipe that is inside the tank barely at the water level. I have both.
You should never remove that venturi line from the overflow unit except when you see something stuck inside that line that needs to be removed. Over time, it tends to get algae buildup or an occasional food particle will get stuck in there. I have hooked up the venturi line to a pump in the sump so that when the unit starts after a power failure, the pump will start the suction of air from the cs90.
I do not know of any kit but I was able to copy my cyclone skimmer setup. It uses a venturi that I was able to get a duplicate of from the manufacturer at no cost and hook that siphon tube form my cs90 to that venturi using a similar pump that my skimmer uses that can house that venturi comfortably.