300g DIY help

[scooterr]

I'm planning the design for my 300g FOWLR tank (72l x 36w x 28h). It will be plywood with glass on the front and 1 side. I will weld an iron frame around all the edges and center bracing on the top , back, and bottom. I have some expirence making ply tanks. My questions are

1. Overflows - total length and holes. I plan on having wetdryfilter.com make my overflows. I will be running a Little giant 5mdsc as a return pump as well as an iwaki 40RLXT (1200 @ 4ft) on a closed loop. I was imaging 1 overflow for the sump and one for the closed loop.

2. Glass thickness- The front (28'' x 72'') and one side (28'' x 36'') are the only sides to be glass. What thickness is recommended?

3. stand materials. I can weld a stand out of steel pipes If need be but I'd rather use 4x4s if possible. Anyone have any expirence with holding up such large tanks? Pics/drawing would be greatly appreciated!

I plan on having a 100g rubbermaid fuge w/ lr, ls, and mangroves as well as a ~50g sump for skimmer (euroreef cs8-2), heaters, probes, etc.

I'm going to try lighting the tank with NO shoplights initially but if that doesn't cut it I'll get VHOs

I'm sure i will come up with more q's along the way but thats it for now. Feel free to give opinions or critisize the system. I'll try to get a CAD drawing for y'all shortly.
TIA!
jeff

 

[SeaRay]

I have a large plywood tank. 8' long, 3' wide, 32" tall. Overflows? Why would you want to put an overflow box? Just drill a hole near the waterline and put a bulkhead fitting and pipe it down to the sump.

My viewing area is 2' tall and 7' wide cut out of the plywood (two thicknesses of 3/4" laminated together). The glass is a few inches larger on all sides. I went with 3/4" glass. That might be a little overkill, but better than to err on the other side. (murphy's law). I can try to get you pics of my setup if your interested.

My tank is in the wall, so it's supported with two 12" block pillars and they're spanned with floor trusses and a 3/4" plywood top. It kinda looked like a heavy duty workbench before I put the tank on it.

Any other questions, let me know, or email me.

 

[scooterr]

I was under the impression that with just drilling a hole in the back and putting a bulkhead and strainer would be loud. I was going to install dursos in the overflows. How much did your glass cost and where did you get it.
TIA
jeff

 

[mongo]

I've built two big plywood tanks, one freshwater (180g) and one saltwater (240g). Both of them are plywood on 3 sides with 2 part epoxy paint from Aquatic Ecosystems and acrylic front. I used 1/2" acrylic and it's plenty strong, easier to cut, and chaper than glass ($180 for an 8'x2' sheet delivered). Got mine from US Plastics. Both of my stands are built out of 4x4 and 2x4. I drilled holes and put in bulkheads with no draining noise. In fact, it's quieter than the old hang-on overflow box I had long time ago. If you want pics of my tanks and stands I can send them.

 

[mongo]

I've built two big plywood tanks, one freshwater (180g) and one saltwater (240g). Both of them are plywood on 3 sides with 2 part epoxy paint from Aquatic Ecosystems and acrylic front. I used 1/2" acrylic and it's plenty strong, easier to cut, and chaper than glass ($180 for an 8'x2' sheet delivered). Got mine from US Plastics. Both of my stands are built out of 4x4 and 2x4. I drilled holes and put in bulkheads with no draining noise. In fact, it's quieter than the old hang-on overflow box I had long time ago. If you want pics of my tanks and stands I can send them.

 

[IcantTHINKofONE]

What's a plywood tank???

 

[mongo]

A tank made with plywood and a glass or acrylic front. They have some advantages like being cheap, easy to customize, durable and lightweight. Downside is that you can only see in one side, unless you put more glass or acrylic sides in. They are perfect for in-wall applications. The last one I put together is a 240g (8x2x2) and cost about $350.

 

[scooterr]

Mongo,
Thanks for the great info and pics. Approximately howmuch do those tanks weigh empty?
I'll have to check out US plastics . For that cheap I'd gladly use acrylic.
How many coats of paint did you use? How did you fasten the ply together? (brackets, screws, drywallscrews, etc)
Do you have a pic of the bulkhead closeup?
Thanks

 

[mongo]

Not sure on the exact weight but think about the weight difference between a 8x4 3/4" sheet of plywood and the same size piece of glass. I would guess a plywood tank weighs half as much or less. I can move mine around myself, but it took two of us to put it on the stand just because it's bulky.
I put on at least 4 coats of paint for the tanks at home. Some of the tanks I built for my lab only have 2 coats (what the manufacturer says to use). I used 2 gallons total for the tank shown above.
The basic design is a 2x4 frame built with deck screws, plenty of wood glue and some angle braces. Depending on the size, you may want to have a number of 2x4 braces on the sides and bottom. When the frame is done I put regular 3/4" plywood in all but the front and paint it. I attached the plywood to the frame with brass screws (before the painting) and wood glue. When your done painting caulk the front, put the acrylic (I screw it into the wood as well) in, caulk all the seams and you're done.
Some people will tell you to use marine grade plywood and not to use brass screws etc but none of these things ever contact the water - if they do your tank is trashed and you have bigger problems!
Here's a picture of my bulkhead... $5 at aquatic ecosystems and takes 2 minutes to install.

 

[scooterr]

Thanks so much Mongo!
You have been of great help.
I'm still in the blue as to hole sizes and numbers. I'll take that post to the main forum to get help.
jeff

 

[Anonymous]

I've never built any DIY tanks, but instead of lots of paint one thing to try might be to line the inside of the tank with flimsier-than-usual acrylic & glue the seams - the plywood would then just do the structural reinforcement, & the acrylic would make sure everything's sealed. Just guessing, though.

 

[mongo]

I've never tried that but I could see problems with sealing the seams between pieces of acrylic. Silicone doesn't stick to acrylic that well (not nearly as well as glass). If the tank was moved, or in the process of filling it, you might get two pieces of acrylic moving in relation to each other. On the other hand, I haven't worked with acrylic glues that much... I do know the paint works really well.

 

[scooterr]

I've thought of that but Painting isn't to much of a hardship (I say that now only having painted a 70g). It is fairly cheap too. I do, however, use acrylic on the bottom to keep rocks and sand from scratching through the paint.

 

[Anonymous]

BTW Mongo I think your dog's possessed...

 

[viking]

Hi,
Here is plywood system i built recently. Still have a couple of things to do but almost there.

Tank details at http://www.fishyfrolics.com/viking/plywood_tank.html

Cheers,
Viking.

 

[fishguru]

Nice looking tank viking, love the marble paint job. Just wondering the dimensions as i didnt see them on your webpage. Guru

 

[viking]

Hi,
Its 2300mm x 800mm x 800mm Thats about 7.5 feet x 2.5 feet x 2.5 feet.
Overall hight from floor to top of hood is 6 foot
Cheers,
Viking.

 

[highrpm]

If you want to just buy a plywood tank, I know where on is at a LFS in Dayton OH. It is roughly 8'X3'deepX2.5'tall.

It needs repainted. It has a metal frame around it, and a stand made from 4X4's and 2X4's

 

[Dumb Guy]

Why not just build the durso overflow into the tank? Kinda like this:

|                     |
|                  _______
|                 |  ___  |
|                 | | | | |
|  water level >> | | | | |
|                     | | |
|  inside of          | | |
|  tank               | | |
|                     | | |
|                     | |||
|_____________________|  v To sump

Just use a bulkhead to go through the back tank wall near the top and then put an elbow on either side. Then plumb the outside elbow down to the sump. Anybody else think this would work?

 

[brokekyle]

Anybody else think this would work?



nope