DIY internal overflow help!! (pics)

Hi all!

I've recently begun working on a relatives old fish tank which i have acquired and am learning about how this all works.

Currently the tank size is 120x60x60 (4ft x 2 x 2)

Is there a specific critera to follow when wanting to install an internal overflow?

I think my first steps are to:

1. Drill hole at bottom of tank
2. Install 2x pieces of either glass or acrylic surrounding the hole to form a box (use aquarium silicone)
3. cut wedges at the top to stop livestock from falling in

Thanks in advance!

Vik

FRONT VIEW OF TANK - http://i.imgur.com/6JkffN0.jpg?1
SIDE VIEW OF TANK - http://i.imgur.com/NRMPR4D.jpg?1
SUMP - http://i.imgur.com/VvyVOB0.jpg?1
RETURN PUMP - http://i.imgur.com/w7YzaSI.jpg?1
RETURN PUMP (closeup Ehiem) - http://i.imgur.com/NsZ8Xhg.jpg?1

 

Hi, and welcome to 3reef Vik.

Bump

 

Most glass tanks of that size have tempered bottoms so it cannot be drilled. You would need to check with the manufacturer to be certain but most tanks over 55 gallons are tempered.
You will probably need to use a hang on back style overflow box such as an Eshopps or similar which are very reliable and pretty inexpensive.

Eheims are very good pumps but the 1250 is a little small for a system of that size. The tank is roughly 120-125 gallons and the 1250 only pumps around 160 GPH at 4 feet of head. Most people will tell you you want around 3x to 5x the display volume for a return flow so say 375 to 600 GPH. I tend to lean towards the 5x to 7x volume myself so would look for a pump that does around 800-900 GPH at 4 to 5 feet of head. At a minimum I would want an Eheim 1262 for that size tank.

 

Thankyou for the warm welcome and replies Corailline & AZDesertRat,

I'll contact the manufacturer and triple check before taking out any drill bits. I think I would rather have an internal due to noise & extra reliability.

But if the glass is tempered would something like the following be okay to use? Reason being is i would prefer not to have to pump water over the edge of the tank using a siphon.

Aquarium overflow box 700gph
http://www.glass-holes.com/images/700 mounted side.jpg

Thank you also for the heads up on the pump. Would it be detrimental to the system to use this pump for the time being? Or definitely shift up towards something that has a little more power in it. (Such as the Ehiem 1262 or above)

 

Found a Eheim 1260 in the sump! Go figure Must have bought the first one, realized it wasn't strong enough and got the second.

Currently just trying to figure out whether the bottom is tempered or not then will proceed with the rest of the project.

 

If the back is not tempered then you can simply drill it at the bottom (instead of the top) and then have the bulkhead in the back wall of the tank instead of in the bottom of the tank. Then build a traditional corner box for it. If you are going to do this much work to the tank, look into a coast-to-coast overflow box and do some research on a Bean overflow (google them both).

Randy