Need help with building a DIY frag tank

[KhanhQ83]

Hello everyone. I want to build my own frag tank (mostly SPS) stationed next to my main display (180g). The area I have is 20"x26" there I'm thinking of a 18"x22"x10" frag tank would go nicely in that space. I have a few questions before I buy the materials.

1. What glass thickness should I get? LFS suggsted 1/4" should be good enough for a small tank, can anybody confirm this?
2. Which silicone should I use? I want to make sure its leak proof and able to withstand small waves because I plan to add an MP10 to it.
3. For lighting, would an AI Sol Nano Blue enough spread?

I need help with question #2 most. Thanks!!

 

[JohnK]

I'll run your numbers through a glass thickness calcualtor when I get home tonight. Do you plan to make this rimless or will it have a eurobrace, centerbrace or other bracing on top?

The common reccomendation for silicone is montmenvue (I spelled that wrong, but it's close) RTV 100 series structural adhesive silicone, 103= Black, 108 = clear. SCS12000 (again, I'm probably off by a letter) is another structural silicone alternative.

Do not use silicone I, Silicone II, or any of the silicones sold by the aquarium complanies. All of these are sealants and not adhesives, not strong enough for tank building.

 

[KhanhQ83]

John, I want this to be a rimless frag tank.

I also want to make it 2" longer so the final dimension is going to be 24"x18"x10"

One more tricky question, I want to drill the return and drain on one of the 18" side, therefore, when buying the pieces, which side should I ask to make it shorter by 0.5" to be "sandwhiched" between (assuming I'm using 1/4" thick glass).

 

[JohnK]

Disclaimer, I have never build a glass tank but I have researched a fair amount so take what I say with a grain of salt and consult other sources before counting on me Whatever we come up with here, I'd suggest double checking on the RC DIY forum. Look for uncleof6's input, it will be cautious to somewhat over cautious, but IMO that's worth the piece of mind.

Typically the ends would be inside the front and back, so it would be the 18" panes that should be cut @1/2" short (so 17.5).

Just as a heads up, if you want this rimless it will have to be more heavily built than a braced tank so that might make the difference between 1/4" or thicker glass. That said, 10" is pretty shallow so 1/4" might work all around anyway. (will check the calculator later). If it's close with 1/4", you can cut the height a bit and then the 1/4" will become safer (thickness is determined by height X longest pane).

Also, will you be building the sides on top of the bottom, or a floating bottom? Sides on top of bottom requires a perfectly flat and solid stand that supports the entire bottom. Floating bottom only needs the stand to support the perimeter, but requires a thicker bottom pane.

 

[KhanhQ83]

I think I will be doing the side on top of bottom. I plan to make a simple stand - a flat 24x18 plywood resting on top of 4 2x2 wooden legs with support bar running through the middle... nothing fancy.

Please run those numbers through your calculator and let me know.. Thanks for your help John

 

[JohnK]

Yup, I'll run the calculator tonight. You might want to go pretty heavy on that stand top, maybe even double up 2 3/4" sheets to be safe. Again, not my expertise but I know that flat bottoms like that need solid and consistent support.

 

[KhanhQ83]

I think I'll make the bottom glass 3/8" just to add extra support.

Sent from my Galaxy Nexus using Tapatalk

 

[JohnK]

That can't hurt, but if the stand is good and flat and the bottom evenly supported it shouldn't be necessary. If the bottom isn't flat or well supported it will probably fail even with a thick bottom.

From what I have read a lot of builders say using a floating bottom is a better design. A flat sheet of glass with several hundred lbs of water on it doesn't take well to even the littlest imperfection.

Again, I'm just relaying what I have picked up from others. Starting a RC DIY thread might get you some more experienced and articulate feedback

 

[KhanhQ83]

Thanks John. I've already started the same thread on RC but not one respond...

If the flatness of the plywood is questionable.... then maybe I can just build a stand without plywood on top but with 2x2 support the perimeter of the tank and maybe a support running across in the middle. That would eliminate the concerns of the plywood flatness.

 

[JohnK]

Thanks John. I've already started the same thread on RC but not one respond...

If the flatness of the plywood is questionable.... then maybe I can just build a stand without plywood on top but with 2x2 support the perimeter of the tank and maybe a support running across in the middle. That would eliminate the concerns of the plywood flatness.

That would be a stand to match a tank with a floating bottom, support around the perimeter.

Be patient on the RC thread, you should get the replies, just gotta wait on the right posters to come along.

 

[JohnK]

Did you start the RC thread in the DIY section? I can't find it?

 

[KhanhQ83]

Yup it's on the 2nd page since no one responded to it lol. It has the same Topic subject and original post.

 

[JohnK]

Ahh, I didn't scroll quite far enough. I bumped it for ya.

 

[KhanhQ83]

Thanks John! did you get a chance the run the numbers through the calculator yet?

 

[JohnK]

Sorry, I fell asleep early last night. I ran it on the calculator I have and it looks like it would be OK with 6mm glass rimless (that's just using a 7.6 safety factor insted of the usual 3.8 for a rimmed tank).

So based on that it Should work but don't start buying glass until someone else can verify that

 

[JohnK]

I PM'd Jim and asked him to take a look at the RC thread and he did post a reply. He also suggested that I encourage you to let your system settle in before building it up more (I hadn't been following the nitrate thread).

This is probably a good time to hone your tank building skills, just don't overcomplicate the new system until it settles in

 

[KhanhQ83]

Jim did send me a pm also about his concerns. Thanks for all your help John.