High Tide Aquatics

Drilled Tank Bottoms

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I'm buying a used 75 gallon tank/cabinet/sump/lights from a friend. Currently it has just one bulkhead in the bottom of the tank for the overflow.

I'd really like to avoid having it pushed out from the wall, so I need a bulkhead in the bottom for the return. I'd also like to try an overflow design like this: http://tinyurl.com/6myxmj

That means I need to drill 3 more holes in the bottom of the tank, for a total of 4. That kind of seems like a lot and I'm worried about the bottom cracking under the weight of the water and rocks. What do you guys think? Should I be concerned?

How about earth quakes? I figure I'll bolt the cabinet to the wall. (it completely encloses the aquarium. It's not possible for the tank to slide off.) Is there anything else I should do to make my new tank earthquake ready? Has anyone had a glass tank crack or come apart in an earthquake?

One idea I had is to put a bed of thinset mortar on the stand underneath the tank. that way the entire bottom would be supported, rather than just the edges. It seems like that might be a good thing, but I'm not sure.
 
If you give them enough space, it should be fine. Most bottom are temper though so double check before drilling otherwise you will end up with bottom less tank.

I wouldn't drill 3 holes just for drain though. 2 are more than enough for tank that size. I don't worry about earth quake. If it's strong enough to break tank, chances are I have tons other important thing to worry. Fish tank would be the last thing.
 
Listen to Phong.

If the bottom is tempered, you are really risking the whole tank. Tempered glass can be drilled, but no guarantees it won't crack. Aim for two holes. While I really like the overflow idea you presented and I might do it myself (my tank has four holes in the bottom), it's not necessary for "quiet" operation. Heck, I'd skip adding holes and run your returns up the back. You need at LEAST 2" from the wall for your tank and that's easily enough space to run 1" returns up the back.

Wait....just a thought...how about this:
Drill three holes in the back, just like the Calflo design. BUT...make them closer to flush with the tank. This is easy to do with some cutting of the PVC "T" and your bulkheads. Then, put your valves down below the tank. Finally, use the single hole in the base for the return. Should meet your needs and drilling the back of the tank is not usually all that bad.
 
From M. Stone on TheKrib:

A word of caution on TEMPERED glass. The conventional wisdom is that you
CAN'T DRILL tempered glass. I have managed to drill a few (1 or 2) tempered
tanks with success, but I've had many crack. So, I don't recomend drilling
tempered glass.

Not that I would do it EVER!
 
I'm pretty sure it's not tempered... otherwise how would that first hole have been drilled? I guess it's possible that it was drilled before the glass was tempered, but it seems unlikely. Once I get the tank I'll double check using polarization.

Why do you say I need 2" between the tank and wall? I was planning on it being flush against the wall.

I think I'd rather have all three drains. It's an extra measure of safety... so long as the bottom doesn't break from being weakened. :/
 
Exactly! Drilled THEN Tempered.

Why 2"? Well, I never go flush do to salt creep and water splashing. Plus, how are you going to run your wires? 2" is just a random measurement, but the idea is solid: you need some space between the tank and the wall.
 
[quote author=Dyngoe link=topic=4285.msg51874#msg51874 date=1218471426]
Not that I would do it EVER!
[/quote]

Yeah, I'm not proposing to drill tempered glass. If it turns out to be tempered, I'll replace the tank or come up with a different solution. For the purposes of this question, please assume it's not tempered.
 
For the purposes of this question.......Yes, you can have four holes in the bottom of your tank. Listen to Phong, just give them enough space between. I think mine are 3" apart.
 
Okay. Thanks!

An earthquake still kind of scares me. A glass tank just -seems- so fragile. I don't like the risk of scratches with acrylic, though, so I guess I'll just go with it and keep my fingers crossed.
 
Maybe I'm missing something so let me recap.

This is a standard Reef Ready 75g and you are thinking about putting 4 wholes in the small space where you currently have a single 1 inch bulk head. Sounds too risky to me.

You could do something like this
Use the 1 existing whole in the bottom for return
Install a coast to coast for great surface skimming with 3 wholes like the set up in the link.
You will need to think about what to do with the RR box around the 1 inch return when you try and put in a coast to coast? Maybe just patch it closed and build your return into the coast to coast? This is just me thinking out loud so I'm sure I'm just scratching the surface or maybe out in left field?
 
I agree with the earthquake concern and scratches on acrylic completely. Same debate I have struggled with for a while. Just a reminder about the calflo setup, nothing says those downtubes need to be close together. You could space them all along the back of the tank and use the PVC pipe to tie your rocks to.

On an slight tangent, I wonder what a rider for full tank replacement and water damage would run in our earthquake policy? Or, how much of the replacement is already covered. I think I'll have to post this as a new thread.

Just one more question that was inspired by Levi...
If this IS a reef ready, then it should have two holes and a box around them. If not, then I'm thinking the bottom MIGHT be non-tempered, but it might be an older tank that had only one hole and anticipated over-the-back returns.
 
[quote author=LeviTillie link=topic=4285.msg51884#msg51884 date=1218473024]
Maybe I'm missing something so let me recap.

This is a standard Reef Ready 75g and you are thinking about putting 4 wholes in the small space where you currently have a single 1 inch bulk head. Sounds too risky to me.

You could do something like this
Use the 1 existing whole in the bottom for return
Install a coast to coast for great surface skimming with 3 wholes like the set up in the link.
You will need to think about what to do with the RR box around the 1 inch return when you try and put in a coast to coast? Maybe just patch it closed and build your return into the coast to coast? This is just me thinking out loud so I'm sure I'm just scratching the surface or maybe out in left field?
[/quote]

Yeah, that's more or less what I'm thinking. I don't have the tank yet (and haven't seen it in person) so I will have to work out the details later, but I'm definitely going to space those holes out, not cram them together inside the existing overflow.
 
If it's a stardard AllGlass tank the overflow is going to be way too cramed for 4 hole for sure. You might be able to get in there but... I doubt it. You could pull out the stock overflow case/box/thingy and make your own out of acrylic, that'd work out but it would eat up your back wall. just some thoughts
 
[quote author=Raddogz link=topic=4285.msg51916#msg51916 date=1218488395]
Great Erin goes to swap and two days later she's upgrading tanks! LOL :D
[/quote]

HA! This was planned before the swap, and it's in addition to my other one, not instead of... but yeah. :D
 
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