adding internal overflow

[lglamb]

(split from other thread)

<a href=showthread.php?s=&postid=7382389#post7382389 target=_blank>Originally posted</a> by hounddog01
Remember if your going across the back with the overflow do not go all the way to the ends. You may want to put something in the corners later.


Could you explain further? Any (uninformed) thots I had
involved putting something in stretching all the way across.

Thanks.

[LegoZ81]

http://a3.cpimg.com/image/79/7F/57912953-303b-02000127-.jpg

[LegoZ81]

you would have 2 rectangle end plates at both sides since they are not butting up to the ends of the tank.

[lglamb]

Yes, but what reasons to not butt up to end of tank?

Just to leave the space for something maybe?

[LegoZ81]

I am pretty sure that is the reasoning. That way if you want to put a powerhead in the rear corner you can. I can't in my setup and have two HUGE Seio 2600's out in the open :(

[Benny Z]

imo it doesn't make much sense not to extend them the full length of the tank. you can still put the powerhead in the corner. my overflow is only 2" deep (front to back), so i only lose 2" of area...not a whole hill of beans.

[tcottle]

Well I just went through this execrise. I added an internal overflow on the end of a 40 gallon breeder. Sump is also a 40 breeder and return pump is an an Eheim 1060. I made the overflow big enough that I could mount a down pointed 90 if I needed to. It doesn't look like I need to.

http://img108.imageshack.us/img108/8809/overflow9uf.jpg (http://imageshack.us)

Originally I had it drilled for a single 3/4" bulkhead but that was too small for the pump so I added a second 3/4" bulkhead. I transitioned to 1" PVC, joined the two ends with a T and piped it into the sump

http://img108.imageshack.us/img108/2401/end16ec.jpg (http://imageshack.us)

Each bulkhead has a capped T with a small hole making it an "external standpipe"

http://img105.imageshack.us/img105/4539/side12mx.jpg (http://imageshack.us)

Here is what I learned:

0. Without the capped and drilled T's the drains would eventually build a siphon, drain a bunch of water and then break siphon.

1. I had the drain pipe well below the water line. Air would build up in the line and clear with a large burb every two seconds or so. Very annoying

2. Shortening the pipe to just below the water line cured #1 but I had an excessive amount of microbubbles in the sump and main tank.

3. I added a filter sock which cured the bubbles but the drain sounds were too loud for me. The air/water mixture moving in the pipes is quite loud. The water surrounding an internal standpipe must damped the sound.

4. I removed the filter sock and mounted a valve just below the water line. It is adjusted so just a few small bubbles pass. Tank now drains well and is silent (yes!)

http://img20.imageshack.us/img20/1650/sump5hu.jpg (http://imageshack.us)

[Benny Z]

my 29/20 setup is very similar. instead of merging the two standpipes, i ran each line directly to the sump.

http://home.insightbb.com/~ben.zimmerman/salt/sumpday2.jpg

i'm using 1" bulkheads and no caps on the tops of the standpipes.

from your pictures it looks like the water level in your box is completely covering the bulkheads? mine aren't completely covered in water and my overflow box is less than 1/2 full of water. i'm using a mag3.

[tcottle]

Yes the water line is over the top. If yours is lower, doesn't is suck air?

[Benny Z]

i guess a little, but it doesn't gurgle. i think that's because i don't have the caps on the tops of the standpipes...there is plenty of breathing room.

here are some current pics...

http://reefcentral.com/gallery/data/500/77080standpipes.jpg

http://reefcentral.com/gallery/data/500/77080overflowbox.jpg

here's the auto topoff device i got from www.autotopoff.com

http://reefcentral.com/gallery/data/500/77080autotopoff.jpg

i highly recommend this device. with such a small return chamber it saves having to keep a constant watch on the water level.