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tank advice (1 Viewer)

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G

Guest

Ok, I have a couple questions.
I'm going to be draining my tank and getting it drilled.
What is the benefit of having an overflow?
Why not just put the holes near the top and use a PVC elbow?

How many gph do you get through a 1" bulkhead, how many through a 1.5" bulkhead?
I'm going to be using a mak4 as my return.

Next question, if you were going to have a tank drilled, how many holes would you get and what is each one for?
I'm thinking 1 or 2 drain holes (depending on size) to the sump/refugium.
1 hole for water changes and hook up a ball valve, my concern there is, I've come across a lot of ball valves that leak a little bit.
1 or 2 holes for closed loop. where do you put them? what kind of pump do you use?
 

Wildfire

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In my perfect world (where the sky is a TOTALLY different color) I would have my tank drilled as such:

2 Corner overflows (both drops and returns) with the return equal diameter of the drops (1" Dia)

1 Center Polygonal overflow with 2 drops and 1 return, the drops being 1" dia and the return being 1.5"

I would have the corner overflows drilled through the BACK of the tank (not the bottom) and have them be as deep as I "needed" with a PVC elbow to direct the water (basically a durso-type standpipe where the "pipe" part is outside of the tank). This would eliminate the overflow taking up any more of the internal water volume than needed, and negate a lot of the "waterfall" effect that keepers experience with the full-depth overflows.

The returns in these corners would enter the same way. This would allow me to run the corner overflows as a "closed loop" system (binding both "drops" and "returns" to a 0-level pump for maximum flow / efficiency).

The center overflow would be a "conventional" overflow down to the sump and pumped back up via a dolphin 3600 (which has a 1.5" output, hence the 1.5" return) I would then break this return (at the water line) into 2 or 3 separate lines back into the water column.

This would give me an open and closed system, while distributing the flow rather evenly around the water column.

Okay, now that I've poured out my soul.... someone tell me why it won't work :D
The Center overflow would
 

dfimble

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Most people find that overflows work better than a 90 degree pipe near the surface because its easier to quite an overflow than a pipe near the surface. I have no personal experience with the pipe near the surface so I am only going by what I have heard.

Overflows take up space and can look ugly.

David
 
OP
OP
G

Guest

Ok, this is a little involved.
Q1- the benefit of an over flow is that it skims the water surface, keeping it clean, which allows for proper gas transfer. the overflow box also holds the water pressure, keeping it off of the drilled glass area. usaully there are two holes in the overrflow, a drain and return.
Q2- why not just drill a bulkhead high and use an elbow? you can, but its loud and prone to be clogged. I did exactly this in a 29 and I had to pick snails and hermits out all the time. If you want to go this route, drill it a little bit lower, and put a Durso standpipe on it, with a screen.
Q3-when in doubt, use a bigger bulkhead. there are stats on bulkhead flows on Reefcentral and I'm sure they have them here. I believe a 1in bulkhead drains 600-800gph.
Q4- how many holes depends on your tank's glass thickness and other limitations such as a tempered glass bottom. I'm putting toghter a 75. it has a 1 1/2in bulkhead in the bottom as a drain to the sump, I have a 1in bulkhead as a drain for the closed loop and a 1/2in bulkhead as the return for the closed loop. the return from the sump will go over the top with a syphon break to prevent overflowing the sump. so you can get away with needing only three bulkheads.
If you want an easy way to drain water for water changes, just put a valve in the closed loop drain so you can just redirect the flow to a bucket .
Q5- what kind of pump for a closed loop? you only need about 800 gph or so IMHO
 
OP
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G

Guest

Ok, with a 1 inch bulkhead for closed loop exit, can you put 2 half inch returns without a problem?
 
OP
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G

Guest

mmmmm.... it might be possible. remember it really depends on your glass. do you know if it is 1/4in, 3/8in? if it is 3/8in you might be able to get away with it. remember that glass cracks under pressure, and you will have pressure coming from the water in the tank and from the water filled plumbing hanging off of it. Remenber you can always return it over the top. It sucks to have a tank break on you, ask holybanana. here's a link to what I have done. keep in mind that I have 1/2in glass.
http://www.mcafoose.org/75gal.htm
 
OP
OP
G

Guest

I have a PVC elbow for an overflow and it is very quiet, skims the surface just fine, and yet to clog in almost 9 months. I think it is very important though to use spa flex PVC with the elbow to make it quiet.
 
OP
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G

Guest

Mrlimpet, how does your siphon break on your return in a power loss?
 
OP
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G

Guest

the return over the top is made out of pvc. You drill a hole in the pvc just under the waterline. when the power turns off, the syphon starts. as the water level drops to the hole, it will start suckin in air, which will break the syphon.
 
OP
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G

Guest

From the pictures, it looks like your return is in the bottom of the tank.
Thats why I was asking.
 
OP
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G

Guest

that is the return for the closed loop. if the power goes out no big deal, because the water has nowhere to drain. the syphon break is for the return from the ecofilter, which goes thru the sqwd and over the top.
 
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