Drilling glass, how many holes is to many?

[CoralFever]

I asked this somewhere else, but hoping to get a better response here.

I am getting ready to drill my 210 (72x24x30 with 1/2 glass) and want to make sure I don't run into issues later. So here is a little system info:

I plan on running the BeanAnimal style overflow with 3 2" holes with a Manta Ray return pump (5200gph) with 2 1" returns(maybe 4). The Manta Ray will also run a manifold that will feed some frag tanks, reactors and a refugium.

Also running a closed loop with a Barracuda(4500gph)and OM 8 way. I removed the mega overflows that came with the tank and will use those 4 holes in the bottom(2 @ 1" and 2 @ 3/ 4") as part of the closed loop. The remaining 4 1" holes will be drilled into the back panel. The inlet for the CL will be 2 holes @ 1 1/2".

The tank will be barebottom so no worries about sand storms. The goal is to keep the the display free of powerheads and equipment but eliminate any dead spots.

With what is mention above I will need to drill the following holes:
3 @ 2"
2 @ 1 1/2"
2-4 @ 1" (for return)
4 @ 1" (for CL)
Total of 11-13 holes in the back panel. The holes will be a minimum of 8" apart (edge to edge) most of them will be 12" apart or more.

So, am I pushing my luck??

I realize that I can send some of the returns over the top but I will have some mesh tops to keep the jumpers in and was trying to keep it clean looking if I can. I can get some pictures if it will help. Any input would be a appreciated.
Thanks

 

[Anthony Calfo]

wow...thats a lot of holes. And a gamut of sizes, For simplicity and tank safety, I'd drill less - albeit larger as needed - holes. The primary structural concern is that floors settle, sink, shift sometimes (even if this is on solid concrete)...plus you working in the tank and having some of yoru weight on the top as you lean in and work, etc. The slightest torquing of a tank for any reason can risk a seam pursing. The extra holes here increase the risk of an outright crack.

My vote if for one large adequate hole for the intake of the CL pump. And use the floor holes for a quieter sump loop. the two 1" holes for drains...and the two 3/4" for returns (from the sump). Its been an increasingly common mistake with the advent of larger and more affordable pumps for reefkeepers to put monster pumps on their sump for no real good reason. Skimmers are and have always been fine with slower loops through the sump. And no one realyl likes a sump that is as noisy as a toilet flushing.

I'm literally saying just drill one extra hole now for the CL pump intake on the display. And yes, get a smaller, quieter and more energy efficient pump for the sump. BTW...have you heard a Barracuda? I own several, thats why I'm asking. Not quiet enough to me for a living space, but a good value and fine for my fishroom.

Love the BeanAnimal overflow

 

[CoralFever]

Thanks for the quick reply. This is the answer I expected and the reason I asked before I drilled all those holes.

My concern with using the floor holes for a return from the sump is that if I have a power failure the entire tank would drain into the sump. No? The sump "should" be able to handle the 200gal but it will be close.

I guess I will have to rethink the returns, looks like a few will go over the top.

Yes I have heard the Barracuda, it has a nice humm to it. All the pumps will be in a fish room behind the tank so the noise shouldn't be to bad, I hope.

 

[Anthony Calfo]

Ah, good to hear. We seem to be on the same page then. As for the returns, yes - they need to be at or above the surface (you can actually run them up high for a quick u and then back down to reduce the risk of back siphoning. Or simply return them at the surface so that the small amount of water that drains can easily be held in the sump. Floor plumbed reurns always need to be high IMO. Check valves cant be trusted here do to organic, organisms and mineral buildups over time in a reef system. There is just too great of a risk of seepage or failure.

But no worries. The sump returns are an insignificant amount of the flow. They are fine at the surface. Your closed loop outlets instead can go safely lower if you like. I frankly never understood the drive for folks to want to have pumps, outlets or returns lower int he tank. With a high enough turnover and slight angles on surface nozzles, there is plenty of turnover in the tank.

Lower pumps or returns are just a design and maintenance burden.

I think you are on the right track, my friend.

 

[Murfman]

Rule of thumb, don't drill any holes, within the diameter of the saw, from the edges or other holes. Other than that, IMO, you should be OK. You have more pressure put on the tank toward the sides, at the bottom, than you do toward the top. I have an acrylic 300 and have 14 holes in mine, 11 on the back and 3 on the bottom.


Being your tank is glass, you might want to less the amount of return holes. Anthony also has a design for a "halo" that goes around the top for returns.

 

[Anthony Calfo]

good advice from Murfan...and a caveat too for acrylic versus glass. The safely acceptable tolerance for deflection ("bowing") on acrylic is much greater than for glass (the rule for glass is half the thickness of the given pane). Also, acrylic has chemical weld seems and as such can tolerate more torquing than a glass tank. Lastly, acrylic tanks have greater bracing at the top (you might call it euro-bracing style akin to glass of that namesake reinforcement); that is huge(!) for adding strength and allowing more holes. The only way to even begin to be comparable with glass if to have what's called in aquarium building (public aquaria) a "four sided capture" (anodized aluminium or coated angle iron/steel that is welded or riveted to form a very strong collar on the top and bottom)

 

[butts182]

you talk about the distance between holes but you didn't mention the distance from the edge of the holes to the edge of the tank...this should also be a consideration.

 

[CoralFever]

good points. the closest holes to the edge will be the 3 2" holes used for the overflow. They will be 1.5 x the diameter of the hole away from the top edge of the tank. Any other holes will be significally more than that.

I googled Anthony's closed loop system and seems like it will be a safer option. I will just need to rethink the mesh tops and somehow build them around the cl returns coming from the top. Is there a link to Anthony's original design?

So I now have it down to 6 holes which seems much more reasonable.
3 2" holes for the overflow
1 2" hole for the cl intake
2 1" holes for the return from the sump

 

[Anthony Calfo]

I've always felt that a loop manifold is far and away the best fine control of flow for a reef tank. Prior to the advent of stream style pumps I said it was the most efficient too, but Tunze and the knockoff stream style pumps are incredibly cheap to run! That said, they are optimal for large tanks but near impossible to finesse on smaller tanks without having spots with too much flow and other spots with not enough. Hence the loop manifold with approx 1 nozzle per ten gall of volume.

 

[dougers31]

Sorry for the hijack... But if I were to drill 2 holes in a 40br(one for main drain and one for emergency), would it be safer to drill one hole on each side of the tank, or 2 holes next to each other with about 2-3in. in between. I realize if I drill one on each side I'll probably have to put in another overflow...

 

[Captain Nemo]

Good luck with this, my thoughts are the less holes the stronger the structural integrity of the glass, but just my .02

 

[Anthony Calfo]

I agree with Captain Nemo...in all cases the less holes the better.

If you are running a sump, just one large or two smaller holes (the number of holes makes no difference in skimmed water quality if you use an internal horizontal overflow...back to one hole potentially)

Dougers31: drilling the short end walls is far safer (they are stronger and have less deflection).