Overflow design question

I have a 90 gallon drilled 2nd hand tank, not sure on brand. It has a pretty large overflow box at the back, just left of center. It's about 8.5" wide x 5" deep, and has a 1.5" bulkhead at the bottom. No pipes come up inside the box. Most stuff I see online, it seems to me that they have a pipe that comes up from the bulkhead, and the water seems to fill the overflow box, and then spill over into the top of the pipe, and down the drain.

Should I have a pipe, or is mine fine? Is this just the design of my overflow? I ask because it's really loud. I put a piece of egg crate at the bottom of the overflow box, over the bulkhead, with a piece of floss on top, and that quieted it down a bit, but I don't really want floss in there.

Help?

 

google Durso Standpipe, it works great for me!

 

You should have a AGA 90g. You should also have a smaller hole. The drain takes a 1" bulkhead, and the other is a 3/4" bulkhead. It does not go by the size of the hole. Yes you need a stand pipe. The small hole is for your return flow, you need a pipe there too and then run your return line into your tank over the oveflow where the little simi circles are.

 

i would look into using both holes as drains because on my 100 a 1 inch drain doesnt give me the flow i need

 

Here is a pic looking straight down into the overflow box, from your description, I don't think that's what I have, there is only one hole down there. The standpipe looks like what I need, but I'm not sure on size. I can tell you that the PVC that I have coming off the bulkhead is in fact 1.5". Does that mean I have a 1.5" bulkhead, and therefore need a 1.5" standpipe?

 

No cool. It sounded like you had a AGA, but not what I was thinking.

So you have a drain, and you have to plumb your return over the back. A 1.5" drain is plenty fro a 90g. The 1" on my 90g is plenty. You just need a stand pipe... most folks use the Durso mentioned with good results.

 

Is the PVC plumbed to the inside threads of the bulkhead or did they attach it to the outside threads where the jamb nnut screws on? I suspect they incorrectly attached it to the outside threads which are not standard pipe thread and can cause problems.
You probably have a 1" bulkhead which is pretty common. It is measured by the size of the pipe that will slip or screw into the inside threads.

Either way you need a standpipe. Durso, Stockman, Hofer GurgleBuster and many others are popular choices, I use the Stockman myself, it works well and is pretty quiet.

 

I think I'm going to stop by Home Depot today and give a go at building a Durso standpipe. AZ, to answer your quesiton, my bulkhead it threaded at the bottom where the jam nut threads on, and inside that bulkhead is where my 1.5" PVC is glued. From your description, it sounds set up correctly. I think I'll just pick up a couple different size reducers and see what fits in the flange at the top of the bulkhead, its not threaded inside, so the standpipe will just have to press fit in.

I still don't quite get the physics of how it will work, but I'm hoping for the best!

 

The standpipe maintains a constant level in the overflow box and gives you the correct air to water mixture so the water flows smoothly. It also eliminates the crashing effect from water falling in to the box.

He must have had that bulkhead drilled special, you usually see 1" bulkheads standard.

 

$7 of PVC from HD and it works great, thanks for the tip all! BTW, it is a 1.5" bulkhead, the whole thing is made from 1.5" schedule 40.