Somebody Please Explain.

[joshso]

I have searched RC trying to learn about overflows. I've learned a little but still have some questions.

I have a 125 gallon AGA that I am going to drill and put internal overflows in.

1. I can't drill the bottom because it is tempered, where do I drill on the back, how far up, how far from the side, how big of a hole.

2. How tall of overflows should I get. My tank measurements are 72"X18"X24".

3. When choosing a return pump, what gph should I get. I know it depends on my overflow but how do I know what is coming out of my tank?

[an411]

I can help give a little info but can not answer everything. you can have 1 or 2 overflows. Pesonally I would have 2 one in each corner. I have a 120 that is 48 inch long and I wish I had 2 overflows for more water movement. But this is up to you. I want to say that the holes that I had drilled were inch and half and that is to just fit the bulkhead. I know that the pipe for teh overflow that I am using is 1 inch. I am not sure on where to drill the holes I would think that it doesn't really matter. I would stay about 2-3 inches from the edge personally. BUt please do not quote me on where to drill cause I dont want to be the blame for a broken tank. my overflows is about 22 inches tall I believes its a standard size for a 24 inch tank. I am sure you can get the dimension from a website. As far as the return pump the overflow gives you the recommended flow but I use a ehiem that is rated for 1200 gallons and I t'd off the return plumbing into my fuge and also you add a ball valve on the return to give you the flow that you need. HTH hopefully let someone else chime in and give some more advice

[joshso]

Thanks for the feedback. I do plan on having 2 overflows. I am going to purchase my overflows from:
http://www.reefmania.net/products-overflows.php
If anyone has used these guys please let me know. Is your Eheim pump enough or would you have rather gone with another pump? Are your bulkheads in the back of your tank or the bottom and how far are yours from the edges?

[Thunk]

I can add to a bit of the info here, the size hole you need in the tank for a 1" bulkhead is 1- 3/4"

I just run the return up over the side of my tank so I dont know about that size. If your useing lockline you could check thier website for what size hole thier stuff uses.

[joshso]

Originally posted by Thunk
If your useing lockline you could check thier website for what size hole thier stuff uses.

What is lockline? I planned on plumbing the tank with pvc. I will probably drill the return holes as well. I guess that I need to figure out where those should go too.

[arts007]

Loc Line is a flexible interlocking hose used in the tank for the return, it allows you to direct the flow

http://www.loc-line.com/products/index.html

[joshso]

Oh yeah, I have seen that. Thanks for the clarification. I am assuming Loc Line is better than pvc due to the fact that you can eliminate elbows and cut back on friction. Is that correct? How durable and sturdy is it?

[arts007]

Its not something that would be used as a full return from the pump, its attached to the pvc comes into the tank

[bertoni]

I'd probably target 350-400 gph through the sump. So just get an appropriate pump, but be sure to count head loss.

[meco65]

The loc line is very durable as it is designed to be used with oils and other chemicals alot more corrosive than salt.

[cdbias2]

That overflow your looking at is for tanks drilled on the bottom.
All you have to do is drill your tank far enough down from the top to allow room for an elbow out of the bulkhead pointing upward. Please look at threads talking about Cali-flows.
You may not think so now but quietness is important if this tank is going to be in a living area.
Also by drilling close to the top, if something ever happened to the bulkhead, you could just drain a little water and repair it.

[joshso]

Originally posted by cdbias2
That overflow your looking at is for tanks drilled on the bottom.
All you have to do is drill your tank far enough down from the top to allow room for an elbow out of the bulkhead pointing upward. Please look at threads talking about Cali-flows.

Thanks, I look into those. I'm assuming I need an elbow wtih a pretty large diameter, so then my bulkhead would have to be large and so on and so forth, correct?

[cdbias2]

The califlows tend to flow into a glass trough that you make around your outfall elbow. Some people make these troughs the entire lenth of the tank.

[joshso]

So let me see if I have this straight. I can drill a hole on both ends of my tank about 2-3" from the water level. Then I can build a trough out of glass that runs the entire length of my tank and that is basically it?

[cdbias2]

Yes, The top of the glass will be your water level. (allow for 1/8" head. ) It will never clog. Some people use the elbow, pointing up with this method but I believe is is an attemp at noise/spalsh control. Any splash will lead to alot of salt creep.