Where to drill for overflows

[Michael Lane]

How should I place drain and return holes? What's the value of an overflow box that is attached to the back of the tank?

I picked up 2 of the 29 gallon aquariums during the dollar/gallon sale. I'm planning to replace a 15 and 20 gallon tank, and I'm looking for some advice on drilling overflows. I'm replacing the 2 side tanks. The new ones are about 6 inches taller, and the return pump is a Jebao DCT-6000 shared between them providing about 250 - 300 gph turnover.

The first set of tanks are using a Herbie overflow with 1 inch pvc, but I placed the drains too high up, so I have trouble keeping a good siphon without creating a vortex. I'll be drilling the back glass since the stands are also storage. I've also seen some overflows that require drilling the back of the tank, but I don't understand what benefit they offer. I was thinking to drill 2 holes (siphon and e-drain) about halfway up and over to the side and enclosing them in an overflow box. Then routing the return either through a hole in the middle (to split the return flow left and right) or the other side. Any recommendations?

Here's a full tank shot including the tanks I'll be replacing.

Here's the sump. I plan to drain the right tank into the refugium on the right side and the left tank will drain into the main drain section on the left.

 

[TheGreatWave]

The eclipse over flow just gives you more room in the tank the typical bottom drilled Reef Ready tanks and is visually unobtrusive in typical installations. I have the larger version of that overflow and you really don't notice it much at all if the back glass is painted black. (I like it a lot. I've built a different system now but carefully tucked the Eclipse away for a future project) The kit you are looking at should include the diamond bit and a template.

They are quite a bit more then a couple of bulkheads and some PVC, but are also quite appropriate in a display tank. In reality your system is really nice with the clear walls at the back, so you may not like the look of a black box on the wall if you don't paint it.

I'm really trying hard to say you need it, the only time were it would be mandatory is if your new tank(s) has a tempered glass bottom i guess.

 

[Michael Lane]

Thanks for describing the use of the drilled overflow box. That makes total sense now. I think I'll go with an external overflow since these tanks are only about 12 inches wide. I think that would work well with a low profile overflow box.

I'm upgrading these tanks as a hobby project, and I think I'll make the external overflow and internal weir. I'm not sure if I should use 1/8 or 3/16 glass (or even 1/4), but I'm planning to do some more research. I think the external overflow makes the hole placement less critical now.

Next step will be to draw some pictures and see what I'll need to get it going!

 

[Michael Lane]

Here's what I'm thinking now. It seems to make sense to go with BeanAnimal overflow since I'm starting from scratch.

• For the external overflow box, does 6"x21"x6" seem reasonable? It seems kind of big, but I"m worried that dropping to 4" wide may be too weak after drilling for 1" bulkheads.
• Are the supports needed?
• Should there be any concern about the return hole in that top corner? It's 2" from the edges.

Since the tank is narrow, I'm considering a 1" acrylic internal weir. I'm not sure if it should have teeth, or if smooth would be fine. I'm thinking this will be at the height of the rim as well.

Any feedback is welcome!

 

[Michael Lane]

I'm about to place the glass order, but need some validation first.

Should I use 5mm or 6mm thick glass for this application?
Are the triangle supports needed; would silicone be strong enough without them?
How much should I reduce the side panels to account for glass thickness and silicone?

 

[Barnabie Mejia]

in my opinion, I would use 1/4" glass (or the closest to it in mm).

suggestion would be is to make the external box the same height as the internal box. this combined with the bean animal set up, it will never overflow on to the flooring. as far as the gussets on the bottom of the external box I don't think it woul hurt to have them there. plus it gives it a pretty cool look.

 

[Amber905]

Any updates on this? I am building a similar tank and wondering how this one worked out. Also, why three drilled holes for the overflow?

How should I place drain and return holes? What's the value of an overflow box that is attached to the back of the tank?

I picked up 2 of the 29 gallon aquariums during the dollar/gallon sale. I'm planning to replace a 15 and 20 gallon tank, and I'm looking for some advice on drilling overflows. I'm replacing the 2 side tanks. The new ones are about 6 inches taller, and the return pump is a Jebao DCT-6000 shared between them providing about 250 - 300 gph turnover.

The first set of tanks are using a Herbie overflow with 1 inch pvc, but I placed the drains too high up, so I have trouble keeping a good siphon without creating a vortex. I'll be drilling the back glass since the stands are also storage. I've also seen some overflows that require drilling the back of the tank, but I don't understand what benefit they offer. I was thinking to drill 2 holes (siphon and e-drain) about halfway up and over to the side and enclosing them in an overflow box. Then routing the return either through a hole in the middle (to split the return flow left and right) or the other side. Any recommendations?

Here's a full tank shot including the tanks I'll be replacing.

Here's the sump. I plan to drain the right tank into the refugium on the right side and the left tank will drain into the main drain section on the left.

 

[Barnabie Mejia]

Any updates on this? I am building a similar tank and wondering how this one worked out. Also, why three drilled holes for the overflow?

More flow for the box = more surface skimming when the return is on..... I am only running two holes on mine but they are 1.5" bulkheads and a 3/4" return.

 

[Michael Lane]

Any updates on this? I am building a similar tank and wondering how this one worked out. Also, why three drilled holes for the overflow?

I haven't finished it yet. I've drilled a million (ok, actually 14) holes, and took a break from the project. I'm at the point where I need to silicone the panels onto the backs of the tanks. I'm not sure how to get everything to line up perfectly. I also don't know how to leak test it now that it's full of holes!

The three holes in the overflow box are for a bean animal style drain. I probably don't need 3 in the back of the tank. I expect to pick this back up after the holidays. I'd be interested in seeing your progress too.

 

[Michael Lane]

I was motivated to make a little more progress on this today. I tried a dry run of the assembly and found that the glass didn't all fit together! None of the panels are square, and the dimensions are off by almost 1/8 of an inch in some cases.

I don't know if that's typical for a glass shop, but I'm pretty disappointed. I spent a couple hours sanding the glass panels with 80 grit on a belt sander. I think I got half of the glass close enough, but I don't know how precise glass has to be.

Here's where I am so far. I've got one of the overflows taped. The other one still needs a bunch of sanding to get it to the right dimensions.

 

[Bigtrout]

I was motivated to make a little more progress on this today. I tried a dry run of the assembly and found that the glass didn't all fit together! None of the panels are square, and the dimensions are off by almost 1/8 of an inch in some cases.

I don't know if that's typical for a glass shop, but I'm pretty disappointed. I spent a couple hours sanding the glass panels with 80 grit on a belt sander. I think I got half of the glass close enough, but I don't know how precise glass has to be.

Here's where I am so far. I've got one of the overflows taped. The other one still needs a bunch of sanding to get it to the right dimensions.

Thats not typical for a glass shop. I went to my glass shop with precise measurements for the 4 baffles in my 40 sump im building. Gave him the measurements. Told him I wanted 1/4 inch glass. He told me to come back in an hour.
Picked the baffles up and they were all square and spot on in measurement. He even buffed all the edges beautifully so no worrys reaching my hand into the sump. Cost was the same as if I bought the cheap big box home improvement thin razor sharp panels and cut/buffed them myself

 

[Michael Lane]

I siliconed the glass panels on last week and finally leak tested them today. Everything was still dry where it's supposed to be after 3 hours. It's looking like success so far!

Maybe just a few more months until I have these in action. I still have to build new tops for these and then figure out plumbing specifics.