Sub-Basic question, what size holes in indoor aquarium?

[Lynn]

Hi,

Been lurking a little, and reading a lot. Still have a lot to learn, but while I'm researching I'm wanting to get a small indoor system started.

I picked up a 'free' leaky 72 gallon (272 liter?) glass aquarium that I'm thinking could eventually be used for a tilapia breeding tank, assuming I can get it resealed... And after reading about the mating and rearing habits of tilapia in Mike Sipe's Hatchery Manual, I think it would be a lot of fun to turn this aquarium into a nice glass indoor breeding tank.

Since there is nothing really to loose with a free aquarium, while I'm working on resealing it I'm also thinking of taking a 'home study course' in drilling glass, and putting holes in the back plate for routing water to/from a water filtration system, and eventually plumb in some sort of grow bed(s) (TBD).

So, the sub-basic question, assuming I am successful at drilling a hole in each rear corner of the back plate, do you think four 1" (2.5 centimeter) holes would allow sufficient water flow to accommodate (as yet undetermined) system expansion?

I can get a 1" diamond hole saw fairly readily. Larger than that may be a challenge.

The safest bet would be to not drill the glass, but I want this indoor tank to be somewhat 'aesthetically pleasing,' so want to hide the plumbing.

I've found information and recommendations on amateur fish-keeping forums that leads me to believe the four 1" holes would be sufficient for external filtration for a 'normal' aquarium, but since I eventually want to build this into a starter aquaponics system I thought I'd ask the question here. Also, I may want to have a higher stocking density than is normal in amateur fish-keeping, so, again, this seems to be the place to ask.

Thanks in advance,

Lynn

ADDED: I guess I should mention that I'm thinking of using a fitting something like this, so with a 1" hole the ID of the fitting would be somewhat smaller. I need to find out what size fittings are locally available before I settle on a hole size, but would appreciate general recommendations on what ID would be appropriate in the above scenario.

[arachdog]

I think one 3/4 inch hole (which is probably the ID of the fitting you'll use) would be more than adequate for a 300L tank at any conceivable stocking density. But to be honest I wouldn't have thought some discreet piping at the back wouldn't be too unsightly. Nearly every aquarium has something of that nature, usually an airlift pump. But its sounds like your heart is set.

If you do decide to do it make sure the hole is super neat around all the edges, ie no chips or scratches. Then smooth it off real good with some emery paper. If you don't do a good enough job then you will create stress points that may start a crack that leads to eventual bottom failure.

[GaryD]

Hi Lynn,

Is this the sort of thing you're contemplating.......here?

The safest bet would be to not drill the glass, but I want this indoor tank to be somewhat 'aesthetically pleasing,' so want to hide the plumbing.

I agree that it would be safest not to drill the glass......particularly if the aquarium is old. (glass hardens over time and becomes more brittle). It should still be possible to come up with something aesthetically pleasing even if there's a pipe or two involved.

The bulkhead fitting you've identified would be useful (and an appropriate size) regardless of whether you drill the glass or not.

Gary

[arachdog]

....particularly if the aquarium is old. (glass hardens over time and becomes more brittle).

That's the first I've head of that Gary. To be honest it sounds like an old wives tale that would sit nicely along side the the glass flowing over time myth. Do you have a source ?

[beelove]

I can get a 1" diamond hole saw fairly readily. Larger than that may be a challenge.

Diamond Pacific sells core drills of nearly any size. The company is located in California. For larger size holes you need a water swivel that attaches to your drill and pumps water down the middle. This can get costly, that one hole could cost you hundreds of dollars. I have the set-up but still dont think i would do it just because glass is unpredictable, nine times out of ten no problems with drilling glass.

[kellenw]

A 1 inch pipe will give you 600 GPH (10 GPM) of gravitational flow as long as you have a minimum of 9 inches of vertical drop.

[GaryD]

Hi,

That's the first I've head of that Gary. To be honest it sounds like an old wives tale that would sit nicely along side the the glass flowing over time myth. Do you have a source ?

It's something that I've believed for a long time. When I googled it, I only found a few "wiki" answer-type things to support it, so it may be an old wive's tale.

Gary

[bunya boy]

Glass a Fluid? We're still not sure!!
http://www.glasslinks.com/newsinfo/physics.htm

Glass is Glass, it can be drilled, holed, ground, melted, powdered and moulded. It can be clear. opaque, translucent or patterned. But I wouldn't be putting holes in a fish tank and expect it to last very long. It can chip, crack and leak far more easily than a "soft" walled subtrate for a fish tank. Use glass as windows in a tank rather than for the main walls, it will save you a lot of trouble I'm sure.

Cheers IanK

[Ravnis]

another option would be to use a two tank system. Have a bin the same height as the tank and have it side by side, then use an upside down U tube to act as a siphon you can then drill a hole in the bin without worrying about damaging your glass tank. The bin just needs to be at least as tall as the water level you want in your aquarium, it could be bigger.

[Lynn]

...But to be honest I wouldn't have thought some discreet piping at the back wouldn't be too unsightly. Nearly every aquarium has something of that nature, usually an airlift pump. But its sounds like your heart is set.

I agree that it would be safest not to drill the glass......particularly if the aquarium is old. (glass hardens over time and becomes more brittle). It should still be possible to come up with something aesthetically pleasing even if there's a pipe or two involved.

Well, you have me convinced. I'll set it up without drilling it, and if we can't live with it, I'll change it some time in the future. 'Course, once it is set up and running, I doubt I'll take it down just to clean up the plumbing.

I think I just wanted to drill it for the challenge, but there are plenty of other challenges awaiting around the house...

Oh, and regarding old glass being brittle, the best answer is that, yes, old glass is more brittle. But the reason is not aging, it's changes in the manufacturing process over the years. Old glass is more brittle, but glass doesn't become more brittle with age.