Aquarium Build Question

[lifeoffaith]

I have never built a tank before, but I just realized my 90 gallon that I had purchased used has virtually no silicone on the inside corners. Of course that means I'm going to have to tear it apart and re-seal if I want to use it. What I was wondering is if I had another 90 gallon, or another tank with the same thickness of glass, how feasible it would be to build a rimless cube to make a 180. Obviously I'll have to buy glass for the bottom, but I was thinking it might be cool to build/buy a center overflow and buy the glass and have them drill it right at the glass place. If I had to I could eurobrace, but I'd prefer it to be rimless. What size holes and how many would I need to do a center overflow like that. I've never run a tank with a sump, so no matter what this will be fun to work on, but I'm just looking for input from those who have built tanks. My understanding is that the depth of the tank dictates the thickness of the glass, and not the volume of the tank, is that correct? So the thickness for a 90 should work for 180 as long as it is the same height?

[lifeoffaith]

Ok, I guess I'll just eurobrace to be safe.

[lifeoffaith]

I still need some help with the size of holes drilled, and can I reuse the overflow for my 90 gallon or will I need to buy a larger one due to the size of the tank. I realized too that this will be actually closer to 260 rather than 180. Even better! If I need to buy/build a larger one I may go center, but not sure since this will be going into the corner anyway. Any thoughts on the center versus corner/back? The back of the tank will probably be painted blue anyway, so I guess it might make most sense to put it there.

[Ron Reefman]

You've totally lost me. You want to put two 90g tanks together to make a 180g tank? Why would that be closer to a 260g tank? Maybe a drawing or two to help us see what you are talking about.

[lifeoffaith]

Sorry, probably should have explained that a bit better. Basically I'm taking the 48 inch front and back of two tanks and then adding a square bottom to build a cube. For some reason i was thinking that the sides of a 90 were 24 inches, but that would make it bigger than a 120 since a standard 90 is 48 x 18 x 26 rather than 48 x 24 x 24 like a 120. So basically it's more like I'm putting two 130 tanks together rather than two 90s (like two 48 x 24 x 26 side by side). It was just a calculation error. So the tank would be roughly 48 x 48 x 26 making it calculate out to 259 gallons.

[lifeoffaith]

I also just realized that at 26 inches in depth, GARF reccomends 1/2" glass for a tank of this size. I will have to have an overflow that will keep it at 24 inches to avoid any issues. So I guess my canopy will have to have a couple inches of coverage on the sides of the tank to cover the water line. It will only be holding 239 rather than 259 with that adjustment since I won't be able to fill all the way.

[calbert0]

Build about a dozen small practice tanks before trying to tackle this beast of a project. Look through post history of user Uncleof6 on threads related to DIY glass tank builds.

[Scottedontknow]

Lol ya I wouldn't do something this big as my first tank!


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[lifeoffaith]

Originally Posted by Scottedontknow

Lol ya I wouldn't do something this big as my first tank!


Sent from my iPhone using Tapatalk

Well you aren't me.

That being said, I will have some smaller pieces that I can play with first (the side pieces from the tanks I'll be using the front and back from). I do want to do it right. One question I had was about the silicone application. Commercially built tanks I see have a bead of silicone on the inside corners, but GARF is saying to just apply to the bottom piece and then put the sides on and clamp them for 24 hours. Don't you want an additional bead on the inside corners?

[lifeoffaith]

Originally Posted by calbert0

Build about a dozen small practice tanks before trying to tackle this beast of a project. Look through post history of user Uncleof6 on threads related to DIY glass tank builds.

I haven't got into the posts really deep, but it looks like Uncleof6 doesn't have any of his own threads? Not saying he isn't knowledgeable. It looks like he's made alot of comments, but was hoping he had some of his own builds to reference.

[Ron Reefman]

This is just my opinion, so I may be dead wrong.

It seems older tanks, and even some new tanks still use a bead of silicone on the inside corners of the tank, including the bottom to side corners. But the Red Sea and CadLight (the 2 I have experience with) don't do the inside bead anymore? I think the inside bead is used by some as an 'extra' layer of security. But I've had older tank that the inside bead had been broken up and scraped away by the use of glass cleaners that use sharp edges and run into the silicone bead and they never leaked.

Ok, so a 260g tank (4'x4'x26"). As a first build I think you are asking for trouble, but that's me. So how thick is the glass? Are you doing any kind of bracing or frame for additional support? Is the side glass going to sit on top of the bottom glass or off the sides of the bottom glass (again, what Red Sea and CadLight are doing now)?

[ktownhero]

Originally Posted by lifeoffaith

Well you aren't me.

Well, more power to you but it sounds like a disaster waiting to happen. I don't feel like bravado and aquarium building (especially a frankenstein tank) mixes well together.

Not in any way trying to be rude, just sharing my gut reaction. You use my reaction in whatever way you see fit!

[lifeoffaith]

Originally Posted by Ron Reefman

This is just my opinion, so I may be dead wrong.

It seems older tanks, and even some new tanks still use a bead of silicone on the inside corners of the tank, including the bottom to side corners. But the Red Sea and CadLight (the 2 I have experience with) don't do the inside bead anymore? I think the inside bead is used by some as an 'extra' layer of security. But I've had older tank that the inside bead had been broken up and scraped away by the use of glass cleaners that use sharp edges and run into the silicone bead and they never leaked.

Ok, so a 260g tank (4'x4'x26"). As a first build I think you are asking for trouble, but that's me. So how thick is the glass? Are you doing any kind of bracing or frame for additional support? Is the side glass going to sit on top of the bottom glass or off the sides of the bottom glass (again, what Red Sea and CadLight are doing now)?

My 90 gallon has a bunch of that inside silicone missing, but the silicone between the glass pieces looks very solid, are you saying you would still use that? It does look like it is just the inside corner silicone that is gone. From my understanding this tank held water before I got it too, so it has that going for it. Of course I would test it first, but just looking for your opinion since you've been around the block a few times more than I in the saltwater world.

I am following GARF's guidelines, but the glass is 3/8" thick. Based on their guidelines I won't want to go to 26 inches with that thickness. Starting at 25 inches it goes to 1/2" thick. So I was going to set my overflow at 24 inches so that the depth doesn't go over 24 inches. So that would make it a 239 gallon tank with an extra 2 inches of glass above the water line. I will be using bracing at the top based on GARF's guidelines as well. The side glass will support the bottom glass (again based on GARF's guidelines). So the side glass will be off of the sides of bottom glass and the bottom glass will be set on 1/4 inch dowels to support it when the side glass is being siliconed to it.

Also, thank you for all of those saying that I'm getting in over my head. I have time, so I may just build a few small tanks since I'll have a little extra glass lying around. I will not be doing this on my own either. I'll have some help. I still have to find out who that will be, but I will find someone to help me, because I think doing it all on my own will not work very well. I do take your suggestions to heart. I don't want to mess up on this, but I do want to do it eventually. It would be great if I could find someone who has done it already in the area who would be willing to help me. I'm sure there is someone, but either way I have time to spare.

[lifeoffaith]

Originally Posted by ktownhero

Well, more power to you but it sounds like a disaster waiting to happen. I don't feel like bravado and aquarium building (especially a frankenstein tank) mixes well together.

Not in any way trying to be rude, just sharing my gut reaction. You use my reaction in whatever way you see fit!

Yeah, don't take that comment wrong, that was said more tongue in cheek, I really do appreciate your opinion and others opinions on this. I really am paying attention to what you're saying.

[uncleof6]

Originally Posted by lifeoffaith

My 90 gallon has a bunch of that inside silicone missing, but the silicone between the glass pieces looks very solid, are you saying you would still use that? It does look like it is just the inside corner silicone that is gone. From my understanding this tank held water before I got it too, so it has that going for it. Of course I would test it first, but just looking for your opinion since you've been around the block a few times more than I in the saltwater world.

I am following GARF's guidelines, but the glass is 3/8" thick. Based on their guidelines I won't want to go to 26 inches with that thickness. Starting at 25 inches it goes to 1/2" thick. So I was going to set my overflow at 24 inches so that the depth doesn't go over 24 inches. So that would make it a 239 gallon tank with an extra 2 inches of glass above the water line. I will be using bracing at the top based on GARF's guidelines as well. The side glass will support the bottom glass (again based on GARF's guidelines). So the side glass will be off of the sides of bottom glass and the bottom glass will be set on 1/4 inch dowels to support it when the side glass is being siliconed to it.

Also, thank you for all of those saying that I'm getting in over my head. I have time, so I may just build a few small tanks since I'll have a little extra glass lying around. I will not be doing this on my own either. I'll have some help. I still have to find out who that will be, but I will find someone to help me, because I think doing it all on my own will not work very well. I do take your suggestions to heart. I don't want to mess up on this, but I do want to do it eventually. It would be great if I could find someone who has done it already in the area who would be willing to help me. I'm sure there is someone, but either way I have time to spare.

Well don't wish to burst your bubble here, however... that is what I do best... :/

GARF, is an excellent resource for most anything reef wise, however they are not exactly an authority on tank construction. They recommend 12mm glass for almost anything, and sorry to say, more often than not, it is an accident waiting to happen. If they are still recommending that you use tape as clamps, you are going to be real big trouble.

At your dimensions, 9mm glass, euro-braced or not, is an accident waiting to happen, and more than likely will. This is not a wobbler a millimeter off. It is way off.

For a euro-braced tank even @ 24" height, you need 15mm glass, and since it is a full floated bottom design, you need a 1" bottom pane. But it is a 1mm wobbler. (Identical to what you would need for a rimless tank bottom pane, same dimensions with a full floated bottom.)

For a rimless of these dimensions you need 19mm sides, and a 1" bottom. This is almost a 1mm wobbler if you go down to 24".

In both cases, you have to realize the bottom is still rimless, and it carries the most pressure.

With a wobbler it is alway safer to go up rather than down. First tank, or not, you are getting in a bit over your head, if for no other reason than you don't know that 9mm is going to be unsafe.

[Ron Reefman]

Originally Posted by lifeoffaith

My 90 gallon has a bunch of that inside silicone missing, but the silicone between the glass pieces looks very solid, are you saying you would still use that? It does look like it is just the inside corner silicone that is gone. From my understanding this tank held water before I got it too, so it has that going for it. Of course I would test it first, but just looking for your opinion since you've been around the block a few times more than I in the saltwater world.

If it had a silicone bead on the inside corners and it's now gone (even partially) will it hold water? Odds are the answer is yes. It's an 'extra' level of protection. It would be like driving your car without seatbelts. Will you survive the drive? Odds are yes. But if something goes wrong...

I build with the extra bead on the inside edge. CadLight and Red Sea don't. I hate to admit it, but I do have a bit more faith (and it's really just faith) in their build ability than I do in my own (as far a tank builds go).

[lifeoffaith]

Originally Posted by Ron Reefman

If it had a silicone bead on the inside corners and it's now gone (even partially) will it hold water? Odds are the answer is yes. It's an 'extra' level of protection. It would be like driving your car without seatbelts. Will you survive the drive? Odds are yes. But if something goes wrong...

I build with the extra bead on the inside edge. CadLight and Red Sea don't. I hate to admit it, but I do have a bit more faith (and it's really just faith) in their build ability than I do in my own (as far a tank builds go).

Gotcha, makes perfect sense. So would you think the tank would be ok to just strip out the rest of the inside silicone and re-silicone that? I've always heard that you need to strip the entire tank of silicone and re-silicone, but if you think that would be safe, I'll just do that and do the 90 I had originally planned. Since it's just a second layer, I assume it would be safe to do that?

Down the road I had planned on building a big tank anyway, but I have just about convinced myself to do a plywood tank anyway and use the glass I had for the glass panels (just two sides since it would be going into a corner), although now uncleof6 has me questioning anything GARF says even about plywood tanks. And their suggestion for a plywood tank at 26 inches deep is 1/2 inch. So I'd have to wait until I can afford heavier duty glass.

uncleof6, do you have a good resource to check glass thickness needed and such? And the whole depth being the determining factor for glass thickness rather than gallons the tank holds isn't accurate?

[uncleof6]

The whole depth is not the determining factor, there is more to it.

There are calculators/resources out there, and I have not seen them all I am sure; but very few are accurate, and they are all predicated on having a full metal rim. E.G. the seams are in compression, rather than tension, as they are with eurobraced or rimless tanks. I have an algorithim that I use. There are a lot of different ways to interperate the results; but I also have 20+ years experience.

I will use some things that you can look up, and that invovles safety factor. Pretty common to run across 3.8 as a minimum safety factor for a tank with a full metal rim. Pretty common to run across 7.6 as a minimum safety factor for a rimless tank. One could assume that euro-braced falls inbetween, but does it really? Remember the bottom is the same as it is for a rimless.

Let's look at your example from above, and 9mm glass, where garf recommends 12mm glass. With your 9mm glass, the safety factor works out to 2.14 for the sides, and 1.52 for the bottom (probably any calculator will produce similar results; differences would be due to being overly optomistic concerning the tensile strength of glass.) Even not including the decrease in safety factor due to the bottom panel (to <2.14) this does not qualify for a full metal rim, let alone a euro-brace. GARF's figure for 12mm comes up to 3.80 for the sides... and 2.69 for the bottom, still not enough.

Let's look at another example, still using GARF. A 72 x 36 x 30 tank. Garf says 12mm. Works out to 1.80/1.10, respectively. To actually get to 3.8, you need 17.41mm/22.32; and since those sizes don't exist, it is 19mm/25mm. Remember this is with a full metal rim!

Seems that something is rotten in Idaho... Don't get me wrong, GARF is great, just not on the tank building thing, for a few reasons; and I am not just bashing on GARF, this is pretty much a standard with online information concerning tank construction.

Have you ever noticed, that *most* rimmed manufactured tanks have a tempered bottom? One can also note that *most* rimmed manufactured tanks that do not have a tempered bottom, will have a thicker bottom panel. Since pressure at any given point in a tank of water is equal in all directions, and pressure increases with depth, it is clear that the greatest pressure is on the bottom panel, and the bottom seam. Not only is the pressure greatest, but the bottom panel carries the weigth--with no support (rimmed tank; and full floated as GARF's design is.) Bottom panel needs to be thicker (stronger) and the seam needs to be wider, than the rest of the tank. Euro-bracing the top, strengthens the tank where the pressure is least, does nothing for the bottom.

Other things, such as even suggesting using tape to hold a tank tank together for curing, is begging for a bad experience: the panels must be held motionless during curing, and tape won't do that. "They" suggest 72 hours cure time for the silicone. Might as well dump the water on the floor with a bucket, you won't have to wait three days... or a year down the road and suddenly the seams pop, because you used tape or straps to clamp for curing. 7 days minimum for a 1/4" bead, but if you let a tank cure for a month, you did not wait too long.

There are too many variables in this, to take chances, and I don't give step by step instructions. I simply try to prevent folks from making very serious mistakes.

On the plywood build, 12mm is probably right... a plywood tank is not limited to the adhesive strength of the silicone. The plywood carries most of the pressure/stress. It is not the same concept.

[OllieNZ]

In regards to the lack of silicone in the corners of your existing tank, I personally wouldn't worry too much (as long as the silicone between the panes is okay). Minimalist silicone work is common place in tanks for fresh water aqua scaping, ADA cube garden for example. I know Uncle is not a fan but I've never heard of one failing.....
These are the seams on my old 48x18x18

[lifeoffaith]

Originally Posted by OllieNZ

In regards to the lack of silicone in the corners of your existing tank, I personally wouldn't worry too much (as long as the silicone between the panes is okay). Minimalist silicone work is common place in tanks for fresh water aqua scaping, ADA cube garden for example. I know Uncle is not a fan but I've never heard of one failing.....
These are the seams on my old 48x18x18

Ok, I was thinking about re-siliconing inside the corners on my 90, just to add that extra layer of security. Anyone else think this is a bad idea, assuming of course that the silicone between the glass is solid? At least that way I have the factory silicone between the glass, and have the factory braces which are all intact.

[OllieNZ]

Originally Posted by lifeoffaith

Ok, I was thinking about re-siliconing inside the corners on my 90, just to add that extra layer of security. Anyone else think this is a bad idea, assuming of course that the silicone between the glass is solid? At least that way I have the factory silicone between the glass, and have the factory braces which are all intact.

No issues with doing that, just make sure you get all the old stuff off without touching the structural seams.

[lifeoffaith]

Sounds good, thanks!