Best way to design overflow & return

[stacyt]

I just got my new 240 gallon tank. The manufacture screwed up the order and only put 1 corner overflow with 1 1" hole. Since the glass is not tempered I told them I would have a glass company drill the other holes for me, and if it breaks they said they will take it back and get me a new tank. I am going to put another overflow in the opposite corner with a 1" hole. Where should I place the return holes? I was thinking somewhere in the top or center sides of the tank.

 

[melbournefl]

actually my best guess would be to put the returns towards the bottom of the tank. My logic here is that if your overflows are pulling water from the top of the tank, then it would only make sense that the return water come in towards the bottom to improve circulation in the tank.
Just my .02 and probably worth even less LOL
Later,
Paul

 

[melbournefl]

sorry, just reread your post and noticed we were talking about a 240 tank I'd also have the other overflow drilled for a 1.5 inch or even 2 inch bulkhead, this will assure your ability to turn the tank 8-10 times per hour.
Again, a lot of this depends on what you're going to be keeping in your tank but I've got 2 - 1.5" overflows in my 220 so my money is at least kinda where my mouth is LOL
Later,
Paul

 

[sal t. nutz]

Definatly do not put the returns at the bottom of the tank. If you lose power, the backflow will completely empty your whole tank into the sump. I am betting your sump can't hold all that water, so your floor will hold it for you. I would have return holes drilled in the overflows, and run the returns right back up through them. Then there would be almost no visable pipes or return outlets. Just a very small outlet at the top of each overflow. My tank has two 3/4" ruturns at the top center of the tank, but they were there when I bought it.

 

[melbournefl]

VERY GOOD POINT Salty! I have checkvalves on my lines and didn't even think to mention it <dummy here> the check valves have handled everything fine when I've done my test runs but of course, when it happens for real, I'll be out of town and the check valves will fail LOL
Later,
Paul

 

[stacyt]

Thanks for all the input. I'm not to worried about things being visible. I'm going to mount the tank in the wall of my living room. So what most people will see is just the tank. On the back side if there is a couple of pipes that wouldn't bother me to much. I though of putting the returns towards the bottom. A freind of mine put his on the side of the tank right in the center. He has a backflow prevention valve that he installed so in the case of power failure it stops the backflow. Also I'm planning on putting a couple of banded sharks in the tank. So maybe this is what I might do. Drill the 2nd overflow to fit a 2" bulkhead. Have this drop water into my skimmer section. Have the skimmer drop the water into a center section where the return pump will be. On the smaller overflow have that drop into a refugium, that overflows into the center section where the return pump would be. Does this sound like a good or bad idea?

 

[melbournefl]

stacy, just one more thing and I'll shut up ... before you have the tank drilled make sure you have the bulkhead in your hand so you know the exact size to drill, sounds silly but trust me, bulkheads vary dramatically from brand-to-brand. Some bulkheads have such a narrow lip around the fitting that even an 1/8 inch error can cause real problems.
Later,
Paul

 

[sal t. nutz]

The flow rate through the large and the small overflow will be the same. Just because 1 overflow bulkhead is smaller than the other doesn't matter, they will both carry water at the same rate. The only way that the bigger bulkhead would carry more water is if your return pump could overpower 2 1" bulkheads, which would require about a 2500 gph pump. But none the less, the smaller bulkhead is still going to provide way too much flow for a refugium. If you want a gravity fed refugium, you will need to split the line from a bulkhead and put a flow valve on that leg. The other leg would run straight to your sump. Does this make sense? In essence, if you do decide to go with a bigger bulkhead in the other overflow, say a 1 1/2" or 2", it provides no increased value. The only benefit that would have is, if the smaller bulkhead got clogged up, then the larger could handle all of the flow. But that still doesn't protect you from what would happen if the larger bulkhead got clogged, as the smaller couldn't handle all of the flow. There is really no sence in having 2 different sized bulkheads.

 

[stacyt]

O.K. So I'll just have the holes for the overflow drilled the same size. Also I'll split the line from 1 of the overflows to feed the refugium, then dump the rest over to the skimmer. Does this sound like I'm on the right track.

 

[broomer5]

Sounds fine to me StacyT
Another option worth mentioning - you can install a tee in the return line. A 1/2" line running from the return tee to the fuge. Redirect a little water to run over to the refugium this way.
Doing so you do not alter or disrupt the drains from the overflow to the sump.
Having refugium feed water under pressure is easier to get it over to the refugium, and is also much easier to regulate the flow with a small 1/2" ball valve.
Either way works though.

 

[sal t. nutz]

Yes Stacy, your way (gravity fed Refugium) or Broomers way (pump fed refugium) will both work just fine. Either way you will need a valve there to slow the flow.

 

[stacyt]

Thanks for everyone's help. Of course before getting the tank drilled I thought I'd check it for leaks. So long story short this tank is going back to the manufacturer and I'll be waiting a few more weeks for them to get me a replacement that is done right.