new 90 gal overflow question?

[tory54]

I am setting up a 90 gal reef tank, plan on having internal overflow custom made for my oceanic tank. Should the overflow go all the way to the bottom of the tank? If not, how tall should it be? Should a standpipe be used? Are they as beneficial as I have read?
Also, from the calculator on this site, it says I should have 1 1/4" drain line, should the return line match this size, or be slightly larger? Thank you for you input.

[mfinn]

You didn't say where the tank was going to be drilled at. The back or on the bottom. If it is the bottom, I would recommend making a durso standpipe. With this setup you need a box that goes from top to bottom.
If you drill the back upper corner, you only need a box big enough to cover the area of the drain.
I have both ways and if you need the drain to be silent the durso is the way to go. However, I don't like the amount of space it takes up in the tank.
I have the back upper corners drilled on my 180 and I used pvc 90's on the inside. It really doesn't make much noise at all. I can't hear it at all 6' away and I have approx. 2000gallons per hour going through it.
The return lines size will depend on the pump you use, but I would plan on using 3/4".

[tory54]

Thank you. My tank will be drilled on the side, I plan on using it as a room divider, so it can be seen from both long sides. So the hole to be drilled will be on the side area so I can hide the plumbing. Can you explain more about how you pvc 90's are set up? I guess you use this instead of the durso.

[flycut]

I have a 90 inside that is pointed down now, witch is not the case in this old picture. And I have a 90 outside the tank that is attached to a 1.5 inch flex pvc. I chose to have the back drilled for 2 reasons. The first being the room it takes when you drill the bottom. The second is if I need to do some work to my overflow, I don't need to empty the whole tank. It is not all that loud and works fine.

http://img.photobucket.com/albums/v252/flycut/overflow.jpg

[mfinn]

On my 180 I have 2-2" bulkheads, 6" in from the edge and 6" down from the top, centerline. On the inside is a 2"- pvc 90 attached to the bulkhead fitting with a very short piece of 2" pvc. The 90 is flush with the bulkhead fitting. I have a piece of pvc in the top of the 90 the is about 1-1/2" with a bunch of slots in it. I also use a product called gutter guard in the 90.
On the outside of the bulkhead fitting(outside of the tank) there is a pvc tee. The top of the tee is a piece of pvc the goes just above the water line in the tank with a cap on it and a hole drilled in the cap(very important). The bottom of the tee is pvc all the way to the sump.
I'm not against the bottom drilled tank/durso setup, in fact I have that on a small tank near my bedroom. It works very well. It does take room out of the tank with the top to bottm overflow box.
Both ideas work for me.

[tory54]

Thanks again. So from what you are saying, you don't need the durso if your hole for the drain is on the side of the tank, only for holes in the bottom of the tank? Question about overflow box, what is yours made out of? I've been told you can use plexi glass, just wondering if that would be durable enough. I also read acrylic can't bond to glass well, so you can't use acrylic, do you know that to be true?

[tory54]

You mentioned a pvc tee outside of the tank, what is the purpose for the upper portion? And why the hole in the cap? Just so I understand the theory.

[tory54]

Flycut,
why did you position the pvc 90 pointing down? What is your overflow box made out of? What are the dimensions of your overflow box and what is your goal for gph of circulation. I haven't set up my tank yet, but have a 90 gal as well. I am having the side drilled, though.

[mfinn]

I believe that you could make a modified durso with a bulkhead on the side or back. Similar to the picture above, by flycut. I would put a tee on the out side with the hole in the cap. The later is to allow the right amount of air in to prevent a flushing action in the drain.
I just made a acyrlic box for my durso stand pipe and I used silicone to glue it to a glass tank. I have used silicone on acyrlic before and it does last for many years, it will probalbly start peeling off after 9-10 years. I had one sump set up with acyrlic baffles and glass sides that lasted 4 years before I sold it to a friend 2 years ago and he hasn't said anything about it failing yet.
I love it when people tell me "you can't do that".
If you want to check out the durso:
www.DursoStandpipes.com

[flycut]

The 90 pointed down make less noise. The dimentions of my box are 6x4x6 thats 6 inches high, 6 inches across and 4 inches deep. It is made out of pvc. If I were to make a new one I would make it longer and deeper. So I would have more linear surface skimming. All in all it is prety fool proof. But my box is not glued to my tank, it is held there by the bulkhead. Hope that helps.

[tory54]

Flycut, That does help, thank you so much.