Input wanted on rear wall overflows

i1justin · #1 10/12/2004, 12:14 AM

Well when it comes to overflows i have taken a liking to the rear drilled wall overflows for the reasons that no "box" has to be installed and take up space in the back of the tank. However the benefits of the overflow box durso can not be utilized. I have used various methods to reduce noise in the past without losing flow on my 75 reef as well as customer tanks (aquarium maintenance). However when setting up 240 gallon reef i have been working on i have come across some issues that i would just like to be addressed and input from all is welcome.

The tank is a 96X24X24 240gal acrylic tank.
The pump running sump return is a sequence stingray with the head could probably push out between 3000-3500 gph into the display.

There are 4 2" overflows drilled into the back wall with 2 1.5" returns (sequence pump running split). I was unable to find locally what i usually use on smaller systems for the plumbing. I setup 2 of the overflows with what i could gather, and they dont keep up. the pump has to be split to run a return to the sump so only 50% or less pressure makes it to the display. Also the sounds are very loud. I am in the process of ordering the plumbing similar to what i use on smaller systems. But since all the larger systems i maintain or have installed have dealt with the overflow boxes i thought i would ask for input before i make my order.
Thanks
Justin Wilde

ReeferMac · #2 10/12/2004, 07:30 AM

I use a device I learned as a "Stockman" overflow:

It's basically a 'T' placed vertically coming out the back of the tank, where the bottom drains down, and the top is capped and drilled w/ an air-hole. Similar to the Durso idea, but works on tanks drilled like yours and mine:

The inside pipe running down is my drain, the one that wraps around is one of the intakes for the closed loop.

- Mac

tonyh67 · #3 10/12/2004, 06:51 PM

I am in the early planning stages of drilling my tank for an overflow/return and have a million questions. I kind of like the idea of no overflow box as well.

ReeferMac, are there just bulkhead screens on the inside of your tank...I would like to see some more images of your plumbing setup? How far down are your holes drilled?

ReeferMac · #4 10/12/2004, 06:59 PM

I think they're about 6" down from the top.

I got the strainers at AquaticEcosystems, along w/ a bunch of other stuff. But what I've found works better for me, is just some perforated tubing. They sell the stuff at AE also, and I had a bunch that I was using for my closed loop (see that long black pipe underwater?).... so I just stuck a short piece of PVC in the elbow to elevate the water level to where I wanted it, and slipped the perf. tubing over it to act as grating. Has worked great for over a year now (knock on wood).

- Mac

rspar · #5 10/12/2004, 07:05 PM

I found having to elbow pointing up on my back drilled cube kinda noisey so I put a box only covers the bulkheads essentially.

http://reefcentral.com/gallery/data/...tank_12-03.jpg

My rock now pretty much covers half of it you can't see the bottom of it now.

rspar · #6 10/12/2004, 07:07 PM

How do you get pics to show from your gallery. Every time I paste a location into IMG I see a little box for a second on the post then it disappear and only my text shows.

tonyh67 · #7 10/12/2004, 07:39 PM

Would there be any reason to drill higher or lower, other than higher to keep the tubing to a minimum?

What are the pros and cons to rear drilled overflows like shown compared to an overflow box or holes drilled in the bottom?

The rear holes sure seem to be a space saver?

ReeferMac · #8 10/12/2004, 07:53 PM

Quote:

Originally posted by rspar
How do you get pics to show from your gallery.

Dunno, not using my gallery.

- Mac

gwrulzmylife · #9 10/12/2004, 11:32 PM

Go for the overflow box on the OUTSIDE of the tank, doesn't steal room from the tank volume. Someone did an overflow that runs clear across the top of the tank on RC, this means that you have NO stagnate areas anywhere on the surface.

tonyh67 · #10 10/13/2004, 05:47 PM

ReeferMac...how is your return set up?

ReeferMac · #11 10/13/2004, 07:27 PM

My return I tried to keep simple. It's just an Iwaki55 running from the sump up to a 1" SeaSwirl (which is no longer swirling, and due to be replaced by an OceansMotions, the next time I get 200 bucks to blow on the tank).

- Mac

AuroraDave · #12 10/13/2004, 07:30 PM

I drilled (actually cut) a horizontal "slot" in the back wall of my tank and glued an overflow box on the outside of my tank. There are photos on my webshots page listed below.

Someone ran a thread on this a while back, but the search function isnt working. I will try to find a link.

I really love this set-up. It saves a lot of space inside the tank and makes aquascaping easier. I used a durso/stockman, so the sound is minimal.

I've set-up systems like yours and to answer the height question... make sure you dont drill the hole too high. Decide if you want the strainer horizontal, or vertical with an elbow. If vertical, you need to allow for the elbow and strainer. I suggest making the elbow-strainer setup and using that as a guide. I also suggest using an elbow with a larger diameter, with reducing couplings, that will help with flow. i.e.: 1-1/2" elbow with 1-1/2 to 1" reducer.

Menards now carries strainers (slip) up to 3" diameter in the plumbing section. They are used for ponds.

Good luck

Macimage · #13 10/13/2004, 10:59 PM

I have an external overflow box.

Joyce

i1justin · #14 10/14/2004, 02:25 PM

thanks for all the input, the setups i usually use is similar to reeferMac but i have a side out let elbow that i use where your T is, this allows me to put the air away from the flowing water and seems to reduce a sucking noise even further.
Aurora could your clarify your post about the hieght and elbows?

AuroraDave · #15 10/14/2004, 02:50 PM

There are a few ways to position the strainer.
-straight out of the bulkhead
-attach elbow to bulkhead & strainer is off of bulkhead
----elbow is pointed up (towards top of water) strainer is vertical
----elbow is pointed sideways and strainer is horizontal

My point was to plan ahead so you leave enough space when drilling the BH. I imagine using a strainer straight out of the BH would be ideal, since no elbow, but space sometimes doesnt allow that.

If you use an elbow, there are a few ways to position it. I think you may get more surface area (and flow) if it is horizontal vs. vertical.

If you do it vertical, make sure BH is drilled far enough down
If you do horizontal, you need to understand at what point the tanks water line will stay in comparison to the strainer openings. Therefore, you dont want to drill BH too low, or the water level will be visible in your tank.
Hope this makes sense