Is this diagram okay?

[zincoxide]

Hi There,
Here is a picture of my tank setup. I was going to put a check valve on the line bringing the water. I have been advised to do the following instead as check valves can apparently fail and they are supposedly noisey.
Can someone please look at the diagram and tell me if taking the line above the water line and hooking it back down to come into the tank if that is good enough to stop it from draining in the even of a power failure.

 

[scsinet]

You will want to drill a small hole in the return pipe right at the desired water line, to break the siphon in the event of a power failure.
If you don't do that, the pipe hooking up over the water line is not enough, as it will form a siphon when the pump stops and flood.

 

[fender]

Also when you do monthly tank maintenance make sure the hole siphon break hole is free of obstruction (algae, corraline, etc.). Something I learned the hard way.

 

[zincoxide]

Originally Posted by fender
Also when you do monthly tank maintenance make sure the hole siphon break hole is free of obstruction (algae, corraline, etc.). Something I learned the hard way.
Confused... If I drill a hole in the return pipe, won't water squirt all over the place when I turn the pipe on?
Thanks.

 

[scsinet]

What you need to do is fire the system up once you have it finished, before you drill holes.
Get it set up the way you want it, and using a piece of tape, pen, whatever, mark the waterline on the return pipe.
Then shut down your system, being sure to break the siphon manually (by lifting the tube off or closing the valve on your return line, and drain the tank down about 4" below your mark or so.
Drill the hole just below the mark.
This way, the hole is normally below the waterline, so no squirting, etc.
Then when the power fails, the tank siphons some, but once that hole is exposed to air, the siphon breaks. The further below the waterline the hole is, the more has to siphon back... so try to get really close to the line.
Of course, I drill my holes just above the waterline, just so I can visually see that they are open and clear by seeing the water squirting out.
Unless you have VERY high flow and pipe pressures, which just above the return jets you shouldn't have, the water won't squirt more than an inch or two, and since it's over the tank, teh water just falls into the tank.
Of course, once you are done with either choice, be sure to fire the system back up, then pull the plug and test it to be sure everything works. You want the holes to be small, but big enough that suffient air can enter to break the siphon quickly... so some experimenting is going to be necessary.

 

[zincoxide]

Okay... I think there is a mis communication on my part here. That pipe that is coming up above the water line is behind the tank and it comes down and connects to a hole in the middle of the glass. I have attached a new diagram which is a side view of it.
I have indicated that there is a hole in the bottom of the "U" (at the top of the tank". That hole isn't there yet, I'm just inquiring ... If I put it there, will it work or will it leak?? If it will leak, then you can see why I am confused.

 

[fender]

Don't put a hole in that setup as it won't work - you'll get wet.
With that setup you will need to make sure your sump can handle water draining from the tank all the way down to the outlet or you will have to tap into the line with a tee and maybe run a small line (3/16in) into the tank (over the top) and have it terminate just at/above the water line.

 

[fender]

Maybe something like this

 

[zincoxide]

Originally Posted by fender
Maybe something like this
Do they make T's that will connect to a 1" pipe on either side and a 1/4" or whatever, coming off of it? If so, I can just run a 1/4" or 1/8" pipe up and over into the tank.
I'm very ticked off... My LFS should've told me this stuff when I wanted that hole drilled in the middle of the tank.
I'm never dealing with these guys again.

 

[fender]

one way to do it: Put a threaded tee in the 1inch pipe. The threaded part being the 90 degree part. Into the threaded port, put in a

[hr]
fitting. It will have 1 inch threads on one side and a 1/4 or 1/8 on the other. To the

[hr]
you can attach a line - make sure you clamp it. Run the line into the tank over the top and exiting right at/just below the water line. You will have to be creative in how to keep it there - you don't want it coming loose.

 

[fender]

Another thing you can do is put a valve on the the plumbing and just not use the hole right now. Just have your return come back up and over like everyone thought you were doing in the first place. Later you could use the hole for a closed loop setup with the hole being the intake and the output(s) coming back up and over the tank back into the water. Having that hole in the tank isn't a bad thing. You just have to be creative in using it safely.

 

[scsinet]

Fenders diagram is what I'd suggest... a thin line extending over the top.
The easiest way to accomplish this is by drilling a small hole in the loop up over the top and cementing in a airline tube coupler with model cement. That will form a perfect connecting point for an airline tube.

 

[zincoxide]

I think I might go with that... Should I use model cement or pvc glue??
Also, fenders design made the return a 90 degree right into the tank and skipped the upside down "U" shape. If I do that, wouldn't gravity alone force it out regardless of air?? So, I was thinking have the return come up and loop in down again and at the top, dripp the air valve. Would that work? Or, am I wrong on the gravity thing??

 

[450rguy]

Yes, fender's design will still feed all the water down to the sump until the level reaches the return bulkhead. You need to couple the two designs. You need the U up above the water line, and then back down to the sump. Put the air line T in the tallest portion of the U. Keep the small line for the siphon break just under the water's surface in the main tank.

 

[fender]

Yep, they are right, you still have to go up. Details, they always get you.

 

[zincoxide]

Okay, thanks for your help... Everyone.
But... Why can't I just put the hole/line right at the very top (which would be above the water line)? Why does it need to be below?

 

[scsinet]

Originally Posted by fender
Yep, they are right, you still have to go up. Details, they always get you.
Yeah whoops. You still have to go up and over. Missed that. :thinking:

 

[fender]

Here I think this might help.

 

[zincoxide]

Okay.. I took your suggestions and I've taken pictures of my setup and the siphon break. Can anyone tell me if they see any problems with it?

 

[scsinet]

Wow ... looks great!

I love the black PVC.
It looks like everything is done perfectly, but one caution.. make sure those siphon breaks end above the water line (or just barely below) or it will defeat the whole purpose.
BTW... might consider painting the back of your tank. With the plumbing coming in in the middle, a plastic roll background may be tough to install... painted will look really sharp.