90 with 2 overflow boxes, question on plumbing
 

Sorry if this has been asked and answered in another previous thread somewhere.

So I'm setting up my new 90 gal tank, my question is my tank has to overflow boxes drilled it it with 2 drains in each.

I've been to several LFS's and they all keep saying they have never heard of having to drilled overflows. It is what it is, working with what I have, t hats how I bought it. Not sure what the previous owners plans were but it's my issue now.

So how do I plumb this thing, do I take 2 pipes coming off the 1st overflow into a tee, then add a shutoff then a elbow routed across to the 2nd overflow same thing it has 2 pipes coming down to a tee and shutoff then from there to the sump?

I have a mag 12 as a pump, and a mag 8 I think for the skimmer, not sure how to route any of that yet. I'm brand new to using a sump. I've had a thriving 29gal bio cube for 2 years feel like I jumped to the majors with no help or guidance.

I'll take pics in a minute.. after the blk paint dries on the back glass.

Thank you in advance
John

You don't want to tie drain lines together. It cuts your capacity to drain in half.

In your case, I would use each overflow box as a separate Herbie drain. Then run the return for the sump over the back of the tank.

So each overflow will contain one syphon and one emergency drain.

Wish I could upload the dang pics, also I wish there was a diagram for what your saying..

So I've read on the herbi drain, just not sure how to go about it. So two separate drain lines from each, straight to the sump?

Foru lines total going into the sump?

Don't worry. We can walk you through all of it.

You are correct. You will have 4 separate drains to the sump.

Each overflow will have:
A drain with a gate valve to adjust flow and achieve a syphon
An emergency drain.

Yes 4 lines to the sump.
Treat each overflow box as a separate unit.

I'm sorry I'm such a new, so both boxes will have one tube straight to the sump no shut of valve, and one tube with one..
When you so have a siphon, how is that achevied?

Of coarse photobucket is giving me a error ��

Then I will have one line, from the return pump. Will it only have one return over the top or can it be spit so there is to over the top returns?

The siphon is in the tube with the GATE VALVE.
This is adjusted to keep water above it's top rim.
There is around a 6" difference in height between the 2 pipes with the emergency higher.

So sorry guys gals, what runs to the skimmer

I run 2 returns over the top with a Sea Swirl on each.

Yeah my overflow boxes have the holes drilled right next to each other. From the images of a herbi the holes were offset

What's the inside look like? Is there an overflow box?

Yes two overflow boxes, and is tjis the correct valve?http://i1079.photobucket.com/albums/...zpsd5hki8ue.jp

Sob I'm using a phone, and this isn't working well. Yes there are 2 boxes

The reason your LFS had never heard of a 90 with dual overflows is that yours is most likely post sale modified.

No. That's a ball valve, used for turning flow on and off.

You need a gate valve, used for adjusting flow.


...if you want a syphon type drain.

Wrong valve - that's a Ball Valve - you want a Gate Valve.

This video should help explain things--->https://www.youtube.com/watch?v=RYhAp6GFNz8

I set up the drains on my 125 this way and it works very well. My drains are silent most of the time. I did my returns a little differently but same principle as in the video. With a 4' tank, I probably wouldn't bother with dual returns though. IMHO.

The trick to keeping the water going over the overflow quiet is to set the Emergency drain standpipe so water doesn't fall more than a few inches into the overflow. The Emergency drain will control the height of the water in the overflow box.

If I were you, I'd consider building a manifold into the return plumbing. You could then feed the skimmer with the Mag12. IMO the Mag12 would produce too much flow through the sump without being throttled back with a ball valve. You would have plenty pumping capacity to run both the skimmer and the display with just the Mag12.

Anecdote: I initially set my 125 up with a Mag12 as the return pump. It was moving way too much water through the sump without being throttled back. The Mag12 is now my mixing station pump and my return pump is now a DCT8000 running at 40%.