Overflow box ?

[1guydude]

So how do u get ur gph from the size of ur overflow box?
Also can i get a recomendation for overflow box size? I know the return pump should be rated about equal...
but not sure how to guess-timate my gph from my box if i build one myself...
anyone ever use weld-on or E6000 either ???
lol
Im moving into a new house and want my tanks sumped and ready to go so i can in hopes just move most the livestock over slowly but the time is coming up and i got work to do!!!!!!!!!!!!!!!!
Im thinkin of putting a 10gal below my 20L... not sure wat size hole or anything...i was thinkin a 6"x 6 1/4"x 2" box though...which is supposed to be 700gph

Ive got it going now but have a new 20L and a spare 10gal sooo.....
These dang return pumps though are spendy i want to get eheim's and theyre supposed to be good.
My 75gal is drilled but i have to measure the holes and guess-timate the box too!
I have to put baffles in the 10gal which are gonna be high! Can i do that?...or should i get a taller tank?
I dont know i need some nuggets of knowledge plz! LOL

 

[2quills]

First things first, I would not go with a 10g sump on a 75g tank. It's too small...you're going to run into issues with micro bubbles. 20L would be better. Even then you could run into issues with bubbles if the flow is too fast. That being said....
Best thing to do is estimate the approximate total gallons for each system and then decide on how much turnover you want for the system. That way you can determine plumbing and pump size.
For drilled tanks with internal overflows it doesn't matter how big you make them as long as they're not too small. Where as with an external overflow you want a pump that closely matches the overflows rating without going over the rated gph of the overflow as it helps to maintain the siphon.
One thing to remember when making your own overflows is that you should first know what size bulkheads you'll be using. That way you don't make it too small since you'll need to install the bulkhead or possibly remove it later for one reason or another.

 

[snakeblitz33]

+1 with what Corey said.
If you are going to do it yourself, I suggest stepping the drain bulkhead up a notch and going with an 1 1/2" drain. Yes, it's a bit oversized, but you wouldn't regret it. 3/4" return bulkhead plenty for a return. On my 90g show, the overflow box was 8x8 and I ran a Mag 12 at 4 1/2' of head. So, basically, from what I gather is that a 16" of overflow teeth for a mag 12 at 4 1/2' of head is enough. That's what I kinda gauge my DIY stuff with. You can take and extrapolate the figures out as necessary.

 

[2quills]

If you want to cheat and know how many gallons per hour of flow you're looking to have there is a calculator on the home page over on the big site that will recommend plumbing and overflow size in linear inches.

 

[snakeblitz33]

Quote:
Originally Posted by 2Quills http:///t/388728/overflow-box#post_3430109
If you want to cheat and know how many gallons per hour of flow you're looking to have there is a calculator on the home page over on the big site that will recommend plumbing and overflow size in linear inches.
+1. Their calculators have saved me a lot of thinking.

 

[1guydude]

well the 75gal has a 50b sump and its already made and everything....im going with the top eheim which is like 982gph return i thinks...
The 10gal will be a sump on my 20L...

 

[snakeblitz33]

Ah, alright. I got yah.
Yeah, I use a 10g on my 20g H. Just gotta baffle it well or else there will be microbubbles everywhere in your display tank.

 

[2quills]

You said the 75g tank is already drilled? For what size bulkhead?
You shouldn't need any more than a couple hundred gph on the 20L system tops.

 

[1guydude]

o okay ur talkin nano size which is good cuz than the return pump will be cheaper

I cant tell u for sure i havent even measuered the holes! LOL its in my storage unit right now and i dont even know anything about the whole plumbing deal! I was just gonna make the overflow box big enough for the holes and from one side of the tank to the other! Its a penninsula tank. With the whole plumbing pvc deal do i need the T at the top right out of the bulkhead? I was hoping not!
Should i use the standard baffling method on my 10gal? Im gonna use E6000 on the acrylic and make a lil space between the baffles and the tank! How close can i put my baffles? Idk just stressed cuz i want it to be done and im moving into the new house hopefully this next month!

 

[2quills]

You don't necessarily need a T on the bulkhead inside of the tank. Most folks put one on the back and then install a cap with a hole drilled in it, and even insert air line tubing, etc. This allows trapped air inside of the drain pipe to vent out. Thus helping to eliminate gurgling noises which are caused from the trapped air trying to escape through the bulkhead.

 

[beaslbob]

Just for anyone reading this thread pls keep in mind the rating on the overflows is the maximum and does not have to be matched with the rate the water is returned to the upper container (usually the display tank).
The overflow will allow the upper container to drain to lower container (usually the sump/refugium/wet dry, etc etc) at whatver rate is being pumped to the upper. So an overflow rated at 600gph will work fine if the water is being pumped to the upper container at say 100gph. or 200gph or 500gph etc etc. But the overflow will not keep up at say 800 gph.
Also you can make an effective HOB overflow from pvc pipe for $20-30 or so.
Just some random thoughts.
worth at most .02