800G DIY Plywood Tank

YesYouCan

New member
So, iv been checking in on the forums for a while now but this is one of my first posts. My intro is short. I have AHDH and OCD and have been driven to build things before i could remember. I am an electrical contractor by trade and Im mechanically inclined but have nor formal training in Construction. I gained interest in the Hobby about 2 years ago and started out with a 7 Gallon Nano thinking it was a great way to start. About 2 weeks later i bought an RSM250 (60gal) as I caught the bug. About 2 months after that, I knew i wanted something bigger.

So it began.

PHASE1

I built my house (another one of my projects). My basement is about 1500sqf and aside from a Movie Theater and a Bathroom the rest was pretty much an open an open playroom for my 5 year old. I had one corner of the basement where i had a storage room with double doors facing into the playroom. This was to become my location for a tank. The room was about 12'x12'. I Removed the double doors and opened the wall up about 8' wide. I cut a 32" door into the back side of the room which was the main stair hall. I began by framing out the platform of the tank. I built a Ply Wood Stand about 28" off the floor. The Display side flush with playroom. The platform was roughly 8 x 5. It was built from 2x4, 2x4 and Birch Ply. I screwed, nailed and PL glued the entire thing. I than built the walls. Using standard ply, the back wall was 4' high x 8 wide and the side walls where 5' wide x 4' tall. I built the three sides like standalone walls (2x4 on 12" center). I PL glue the 1" Birch Ply to the walls which were screwed and nailed together. I than added another layer of ply to the bottom as well as a 4x4 along the front leading edge (playroom side). I than PL glued the 3 walls and Lag Bolted them down (from the outside obviously) thru the Base Deck + Lagged the sides to the rear wall + the front 4x4 + added and lagged another 4x4 at the top edge of the front wall. This front wall was also connected/nailed/lagged to the header of the original door that was there. And so I had built the Box. I used Metal Strap (typically plumbers use it to support pipes). I wrapped/strapped the box around the 4 sides. I patched up the front wall so that i now had a 92" x 40" Display.

PHASE2

After doing a whole bunch of research i decided to use BLUEMAX rubber coating. I first filled any and all seams with PL construction adhesive. I than put about 10 coats of the BLUEMAX on all the exposed wood - This was the most time consuming part as it only took an hour to coat - I gave it a day to dry (so this process took a couple weeks). At this point i had to start looking for the display glass. I called in some favors and got pricing for glass about 96x48 as my goal was to have the glass overlap my edges my as much as possible. I figured i didnt want to rely on silicon alone and figure the pressure against the glass would seal it itself. Dispite having FRIENDS who had FRIENDS my glass quotes for a 1" thick piece was well over 2k. Ultimately, i ended up spending a little more than $800 for a piece of Starphire glass shipped up from Glasscages. Besides needing 4 friends to put it in and take it out of my truck - it wasn't a big deal. I used about 8 tubes of sillicone as a ton of what i read was that silicone doesnt stick to the bluemax (but remember my thought was that Water Pressure is going to hold this in place and i wasn't really concerned if it STUCK like one would think. I let the caulk stiffen up than me and 3 of my guys slipped the glass in from the front and pushed it up against the 4x4 framing. I let this dry up for a day or so than used a whole bunch more of that BLUEMAX and slopped it all over the corners.

..And thats how i built my DIY plywood tank which has been running for over a year now with NO LEAKs nor any dead fish due to strange chemicals that others would have you believe you shouldn't be using.

...If anyone is interested ill continue my story as to how i built my Filters, Lights, Sprayfoam Overflows and Rocks as well as used Playground Sand sold at Home Depot for $5 a 30lb bag.

- YES YOU CAN DO IT. Dont let the misconceptions of others keep you from trying to build a your dreams.
 
I did my old 800 similar, except I fiberglassed matted all inside corners then applied a potable 2part expoxy paint on top of that for 3-4 coats.

My tank was 84x48x48

Can't wait til I can do it again.
 
I did my old 800 similar, except I fiberglassed matted all inside corners then applied a potable 2part expoxy paint on top of that for 3-4 coats.

My tank was 84x48x48

Can't wait til I can do it again.

I looked at that idea briefly than knowing how much the expoxy smelt it wasnt an option. I tried not to over think it while trying not to make a stupid mistake. PL Glue bonds to pretty much anything. I glues in between the seamed walls as well as the joints. That by itself would have held water so the layers of Bluemax to me was almost a barrier to keep the toxic glue from seaping into the tank.

All in i spent not much more than 2k on this. Prior to pulling the trigger I was going to buy an Acrylic 300 for well over that which was just for the tank itself.
 
I have been wanting to try a full-sheet plywood build like yours but have been unable to find info on building the structural support. Did you follow any guidelines to build your 2x4" frame or did you just guess? Similarly for the glass thickness, what did you follow to determine the 1" thickness?

Also, what is that fish that is half brown, half white with the forked tail?

Thx

Dave.M
 
I have been wanting to try a full-sheet plywood build like yours but have been unable to find info on building the structural support. Did you follow any guidelines to build your 2x4" frame or did you just guess? Similarly for the glass thickness, what did you follow to determine the 1" thickness?

Also, what is that fish that is half brown, half white with the forked tail?

Thx

Dave.M

I did my own math for the stand. I used conventional framing - where the legs of the stand were in line with the posts of the wall. I however have three rows Front/Middle/Rear which i staggered the Middle set of legs. And they arnt really LEGS but more like extensions of the wall that just are covered. I did Double up each leg post so that basically I have 15 x 4x4 posts under the tank.

The Glass was an educated guess. I researched alot about it - and it all boils down to the height of the Display which is what creates the pressure. I saw a bunch of guys working working solutions using glass alot thinner than the RECOMMENDED thickness. I figured that since I have a full Header across the top plus about 5" all around of overlap - I would be safe to go a little thinner.

A scary part of the build was when i first filled it - I had strapping around the three sides but nothing bracing the back wall to the front header. I thought id be fine until i noticed the back wall Bowing about 1". I was like holy **** - its actually bowing an 8' 4x4 post. I drained half the tank and euro braced it with 2 x 2x4 front header to back wall + I added another plate across the rear wall. Its still has me thinking thou - if that pressure bowed the back wall like that (which is FRAMED 12" on center with 1" Ply on its face than whats going on with the glass which has NO framing supporting its face.

I stopped worring (well not really) about a month or so of it being up and running. My 5 year old has hit it a few times with his toys and it had me flinching a bit but all is well.

Also, I think the fish you are talking about is an Lyretail Hogfish (Orange and White). http://www.liveaquaria.com/images/categories/product/p-76619-lyretail-hogfish.jpg
 
what are you guys doing about humidity with tanks this large isn't it destroying your house?

I have a 2 Remote Fan Units (Fantech) @ about 250cfm each Exhausting the tank Room Air below the drop ceiling outdoors + 1 4" Intake drawing air back in above the ceiling - sorta creating a convection. Ill prob close off the return air since the pulling 20 degree winter air back into an room thats about 80 degrees is destine to cause some rain. I do go thru about 15-20 Gals a week (or so it seems). Im checking daily to see if its leaking out somewhere but all is dry.

My Sump is a 100G Rubbermaid Can with a Hammer Head returning about 2600 GPH. I built a unique (or so i think) overflow. I punched 3 x 2" Holes thru the mid point of the side wall. These 2" Bulkheads are 90 turned up and transition into 3" PVC which have a 4" Reducer glued to the top at the water line. I slotted the 4" edges. In each of the 3 stacks a 3x7 Filter sock fits perfectly into the 4" Reducer and extends down into the 3" stack. On the outside the 2" are T'd each with a 1" vent stack above the water level which indirectly has been acting like a skimmer as foam boils out the top of the vents . All 3 join and dump into my 100G Rubbermaid - but they dump into a three Drawer pastic storage thingy that you have seen before. I drilled a 2" hole in the top and about 50 holes in each tray. Each Tray has filter material. I ideally keep the sum 1/2 filled. I also filled 1/4 of the Can w/ about 150lbs of Clay Brick (as i read somewhere that Red Clay Brick was a could bio filter. Im not sure how much if at all thy help - but i had them and figured i know pretty quickly if they were a problem or not. I have a small portion of the return line diverted into a 30 Gal Glass Tank where I have Reef Octopus skimming some crap out of the water. I also have a DIablo pulling and returning to the Display - pushing thru a dual reactor filled with Carbon. Since Im Fish Only im not overly concerned and feel its doing a good job keeping the water clear. I also added a third Diablo pushing about 800GPH thru 2 to 25W UV Pond Filters.

Knocking on Wood that I haven't had any sick fish or fish die in front of me. I will say that Iv had a fair amount of fish just disappear without a trace. No bones, floating carcasses, piece trapped in my overflows, ect. I haven't been real thoughtful with mixing fish - for the most part everyone is happy however my Pink-Tail Trigger who is about 7" has been chasing my Blue Niger Trigger whos about 5" now back behind my overflow wall for the past few months.

My lighting is a Combo of 5 x 30W LED Fixtures (like the Flood Light Versions) in addition to 8 x 15k LED PAR30s (thanks goodness for Amazon Prime being linked to my AMEX Rewards Points). I also build a DIY Night Light w/ 30 x 3w Cree 455 w/ 10 x 3w Cree 600nm?).

Im in the Home Automation Business so my whole setup is completely automated - even my Custom Corkscrew Autofeeder which has a 5 Gal Reserve (not that i have every filled it but I had left it alone for 5 days while i went on a Family Vaca). My Glass was a little dirty but everyone was happily awaiting my arrival.
 
3lc_cBr8xKqBPwwyrkUoAmTZAPQewVghpLM4_yfoSLXyMYvO-VdZrga4MhHWMmFc55_4eh4pMo4=w2024-h931


Little help to have an image display in line, so folks get what you're talking about :)
 
I built a full plywood sheet footprint tank some years ago. Not quite as tall (30" versus 48") but still a nice big tank. Built it in situ so when the time came to move it fell victim to the sawzall. I did have some oozing issues which necessitated emptying the tank at about the one year mark for repairs. If circumstances were right, I'd definately consider doing it again.

I built mine out if dual thicknesses of A/C plywood, coated all interior surfaces with P&L epoxy paint prior to assembly, screwed all panels together, and used silicone sealant on all interior seams. Tank ran for about five years. A RODI reservoir that a made at the same time with the same approach has remained in service ever since (22 years) so a properly designed and built plywood tank can last.

I used 3/4" glass for the front and one end (glass siliconed from the inside against the plywood front, whic was cutout); used a C2C overlow on the other end (before it was called C2C:)).
 
Last edited:
Looking good. I don't know why people are so afraid of plywood builds. Any more info on the rock wall you have on one end was done?
 
I built my stand out of rebar enforced, concrete core cinderblocks then lvled them with plywood and foam on top
 
Back
Top