Glass? Or Acrylic? For an overflow box.

Discussion in 'I made this!' started by riggles17, Aug 16, 2016.

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  1. riggles17

    riggles17 Plankton

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    Aug 16, 2016
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    Hello ladies and gents,

    This overflow box isn't going on a reef tank (unfortunately) but I am stealing an idea from the reefing community [​IMG] . I'm going to be setting up a Herbie overflow on a 6 foot freshwater tank and I'll be drilling the tank myself. My question is whether I should stack the drains one on top of the other on one side of the tank and use a vertical box OR if I should drill the holes horizontally beside each other along one pane of glass and use a horizontal box.

    Following the community input, the next big question is glass or acrylic for the overflow? I know acrylic doesn't bond well to glass, but I have seen threads online about people having some degree of success in the past with acrylic bonded to glass as their internal overflow box but I'd rather do it right and not have to worry about it.

    I've also seen threads where people have built acrylic boxes and then sealed them using a gasket between the bulkhead and the inside of the box and then another bulkhead between the outside of the box and the glass of tank itself, if that is necessary I can do that too but I may need different bulkheads than the ones I've already ordered.

    Thanks in advance everyone
     
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  3. dienerman

    dienerman Corkscrew Tentacle Anemone

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    So if it helps you, i have made two coast to coast / bean animal overflows for 6 ft tanks. In both i have used glass with good results. They have beed very easy to build and i am very happy with how quiet the tank is. As a brief description, i built a 4x4 glad box inside the back of the tank that extends the length of the tank. The top edge is about 1/4 inch below where i want the water level. I then drilled 6 bulkheads, 3 on each side. One is for total suction and has a valve down in the sump for control. The second if for a small amount of additional flow beyond what the total suction can take. The third has a 90 degree elbow pointed up as an emergency overflow in case one of the first two get clogged. The remaining three are the same as the first 3. There are many videos and build diagrams so i won't bore you with details. The advantages are that its very quiet, very reliable and not prone to causing flooding. It also takes off the top layer of your water in a continuous sheet so there is no scum build up on top of the water and gives good oxygen exchange. I would think that it would work just as well on a fresh water system. It is much better than any type of external overflow which I always find to be concerning due to potential flooding issues. Hope this is what you were looking for. Good luck!
     
  4. riggles17

    riggles17 Plankton

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    That is helpful thanks. I was more looking for exactly how it was sealed to the tank, I am assuming you siliconed it in place? I am undecided between Herbie and Bean Animal, but I may do a Bean Animal permitting I don't need to tap the second pipe that needs the airline extending out of the top of the cap. I dont have a tap for PVC pieces but I do prefer the idea of the Bean Animal.
     
  5. dienerman

    dienerman Corkscrew Tentacle Anemone

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    Location:
    West Chester, Pennsylvania
    No need for any air line extending out of any pipe with the bean animal. Toddsails is the expert here i think and did a great build thread on his system. Everything good i have done i copied from him! I used GE type 1 silicone. and it works very well. It needs to support almost no weight since they whole thing is in the water. I did everything in glass which i found to be just as easy or easier than acrylic. I think i paid about $70 for the two 6 ft pieces of glass which is much cheaper than acrylic. The silicone binds well with glass-glass so there are no issues there. I got my bulkheads and glass hole saw from Glassholes.com for about $50 and all my PVC pipes and valves were less than that. I have no regrets with how i did it. What ever you do, remember that this is the tank you will have for a while and changes are difficult or impossible after you decide what to do. Make sure you are going to be happy long term both with how it operates and how it looks. Noise was also an issue for me since my tank is in my living room (where it should be!)
     
  6. riggles17

    riggles17 Plankton

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    Are you referring to the 320 gallon build? I had seen that awhile back and just revisited it and it appears to me that he had airline coming out of the top of one of his drains in most of the early pictures. I could be looking at the wrong thread though!

    I have been going through Bean Animals threads and I seem to be missing where he actually gives dimensions for bulkhead placement, overflow box size, where the elbows should terminate inside the overflow box. I think I managed to figure out that 3/4"-1" is where the downturned elbow in full siphon mode should end from the bottom of the overflow box.

    I found this snippet from a thread on another site and I quote

    "First you need to measure down from the top edge of the glass, not the top of the trim. Also, the top of the weir should be 1" down from the top edge of the glass (which puts it even with the bottom of the trim on the outside of the tank. You need around a 1" water drop, from tank water level to overflow water level, and the water level needs to rise above the dry emergency inlet to purge the air from the siphon line. Running water level in the overflow is generally ~ the top of the down turned elbow. This puts the top of the elbow down from the top edge of the glass a minimum of 2", plus half the od of the elbow gives you the hole center, it is ~11/16 of an inch so figure 3/4". This puts the center for 1" bulkheads, 2 3/4" down from the top edge of the glass, or 1 3/4" from the bottom edge of the trim. This puts the outside edge of the hole, 1 7/8" down from the top edge of the glass--or around 2 3/8" from the top edge of the trim. Gives close to 3" of head pressure on the siphon, to purge the air, without overflowing the tank."

    I'm not sure what is meant by the "top edge of the glass not the top edge of the trim" and similarly when mentioned the top of the weir should be 1" from the top edge of the glass.

    I plan on drilling the bulkheads first and then building my overflow box around them as necessary. My bulkheads are 1" so should they be 2.5" down from the VERY top of the tank's outer trim?
     
    Last edited: Aug 16, 2016