Help Needed: Building a fish tank stand

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Forum topic by Jim posted 01-23-2014 04:12 AM 6047 views 1 time favorited 16 replies Add to Favorites Watch
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150 posts in 3828 days

01-23-2014 04:12 AM

Topic tags/keywords: fish tank designing furniture moisture

Hey guys, it’s been a while! I’ve got a friend desperately in need of a new fish tank stand and I’ve finally agreed to help. I just need some input because I don’t want her to have the same issues she’s got in her current stand. It’s a marine tank system, 90 gallon tank, water, rock/coral, sand. VERY heavy. The current stand has issues where the walls are starting to bow (they are particle board covered in a vinyl) and there is a smaller acrylic tank in the bottom of the stand to help the ecosystem somehow (she knows what it does but I don’t lol, a filter system would be my best guess). This second tank has no lid, and all the euro hinges on the doors of the stand are covered in solid rust, and screw heads in the panels, solid rust, it’s just a moisture mess.

Here’s my proposal to you guys:
1.) Weight concern – would 2×4 or2×6 construction on the framework be enough to hold that much weight?

Of course plywood will come into effect for the sides, and probably 3/4” for a top and bottom as well. I saw a post by fellow ‘Jock JoeyG ( that looked reassuring but I wanted a 2nd opinion from my other fellow ‘Jocks.

2.) Moisture concern – How do I prevent the moisture issues they are having right now? I considered making a lid for the smaller acrylic tank out of some thick acrylic I have laying around first of all. Either just have it set there on top, or hinged. Although I’d guess the hinges would rust as well. I also thought about either finishing the inside of the cabinet in polyurethane, or even using FRP (Fiberglass Resin Paneling) board that’s used in bathroom wall covering and lining the insides with that. Both options are an attempt to prevent any warping or extra movement in the wood. My friend’s husband wondered about maybe adding a small fan to vent the stand as well. My concern here was all the nearby furniture and the salt and moisture content of the vented air and the damage that could cause.

Any input would be appreciated, I don’t mind putting the work into it but I don’t want to be the one responsible for them losing their tank (or their kids getting hurt.) Thanks guys!

-- -- Jim - Kokomo, Indiana

16 replies so far

View Randy_ATX's profile


881 posts in 2948 days

#1 posted 01-23-2014 04:28 AM

The water is around 800lbs, tank probably 200lbs, sand etc., another 200lbs. Figure around 1200lbs. I used to have salt (marine) tanks and even built a stand many years ago. For the decking I would use two sheets of 3/4 ply glued and screwed together. I would run some horizontal structure under the decking. I tend to over build things but I dont think you could go wrong with 4×4’s as vertical support around the inside of the cabinet – 4 on the outside corners and 2 in the center (front and back). I would skip the fan idea. Make sure to use corrosion resistant screws/hardware. The salt is what is rusting (corroding) everything and it gets all over. If the current stand is starting to bow as you said, they had better start draining some of the water to get some weight removed! My mom had a 125 gallon that started leaking when a corner seal let loose. It was a mess. Good luck.

-- Randy -- Austin, TX by way of Northwest (Woodville), OH

View Aj2's profile


2479 posts in 2304 days

#2 posted 01-23-2014 04:32 AM

Hi Jim , I have built many reef tanks for a friend that services tanks.
2×4 plywood gorilla glue and stainless steel screws.
Since the back of the stand is open no venting is needed, My friend did put fans in the canopy to vent heat and moisture.
90 gal is not too big,it’s a good idea to get your top flat.And check the floor were the stand will sit.Shim the bottom of the stand if needed.

-- Aj

View Jim's profile


150 posts in 3828 days

#3 posted 01-23-2014 04:39 AM

Thanks for the quick responses guys. I’m just like you Randy, I go overkill on my builds to be certain I don’t regret anything. Backbevel, we had talked about leaving the back open, my concern would be allowing all that salt/moisture to vent all over, would it effect the other furniture and electronics in the surrounding area? I’ve also considered lining the inner cabinet with something like a truck bed liner paint, just in case there are any spills/leaks. Thanks again guys, and if anyone else has anything to input on the subject I’m still open to ideas.

-- -- Jim - Kokomo, Indiana

View TravisH's profile


683 posts in 2441 days

#4 posted 01-23-2014 04:56 AM

As long as the stand is built properly various methods/materials are fine for construction. I have built several stands over the years and 2×4 or 4×4 construction is rather straight forward and easily will support a tank that size. A properly constructed stand from 3/4 ply will also work with no issues.

Salt water getting everywhere is more about “sloppy” set up or sloppy maintenance techniques and easy to avoid as long as care is given when working in and setting up the tank. I have no issues with rust after 7 years on my newest stand and have some of the junk particle board stands that lasted well over 20 years with no visible damage. Salt gets everywhere from two means and both relate to water being where it shouldn’t be. Either condensation (if stand boxed in) and resulting salt creep using these “highways” or splashing. Fans are sometimes utilized in the sump area to help get some evaporative cooling but typically stands are open back and readily ventilate on their own.

No need to go to extremes to seal the interior of the stand. Many options to seal the interior and hard to go wrong. Just anything that seal the wood will work. A lot like to just paint with a white enamel paint in the sump area because it makes seeing things easier.

GARF stands are usually the DIY build of choice but often because they don’t take much skill in building. You can skin the stand afterwards for looks.

Simple open concept 4×4 stand.

More traditional 2×4 or 4×4 build with 3×4 ply top and inside base (overkill but what I had). Then all the interior skinned with baltic birch. Exterior skinned with cherry ply and finished off with cherry molding.

Then a 3/4 oak ply build. I didn’t make this one but it has been in use since early 80’s with no issues with an ~ 100 g tank.

View Armandhammer's profile


235 posts in 2131 days

#5 posted 01-23-2014 04:58 AM

2×4’s are plenty strong. I build my stand for my 75g tank out of 2×3s. Rock solid for 8 years. Like others said, flat is key. If it’s uneven the water will put more pressure on the glass at the lowest point and could cause a seam failure.

View Jim's profile


150 posts in 3828 days

#6 posted 01-23-2014 12:19 PM

Awesome guys. Thank you all for the great input! I’m going to start designing today and hopefully start the project this weekend to relieve her stress that’s been building. I appreciate all the great info (and pics). Now the hardest part: figuring out what to charge lol. Thanks again everyone. I’ll post pics once it’s done and setup.

-- -- Jim - Kokomo, Indiana

View NoLongerHere's profile


893 posts in 3182 days

#7 posted 01-23-2014 01:42 PM

It seems that adding plywood to a 2×4 frame is way overkill and adds a lot more work. one or the other.

If you build a plywood cabinet out of prefinished maple (not PB) plywood with a center divider or a 1 1/2×3 double plywood vertical rib support behind the face frame, double the plywood on top, single layer for the floor and skin the sides in hardwood panels it will be plenty strong and you won’t have to worry about finishing the inside. The look is killer too.

Having a 3/4 plywood back adds much needed strength and rigidity. It also cuts down on the loud motor noise and keeps any mess inside and the dust out. You can cut vent slits at the top.

I thought about adding formica to the floor inside but decided the prefinished plywood finish was good enough – so far so good. I sealed the inside edges so water could never get under it from inside.

The extra tank is for an RO system and should have a lid on it. no need to hinge it. You have to seal as much as possible, even so, you will still have to clean under there every six months to get rid of the salt residue. no fan needed – just adds noise.

I hope you consider making the face frame out of solid wood and not out of 3/4” plywood with doors cut out.

recessed doors with 1/4” paneling are flimsy and look cheap, like all the store bought stands. A face frame and raised panel doors really make a difference. You can custom order the RP doors too.

make the top shallow to make it easy to reach for daily feeding. mine is 6 1/4” tall and overlaps 2” to cover the top band on the tank. They will need to buy glass tops with lids so make access holes for them.

View TravisH's profile


683 posts in 2441 days

#8 posted 01-23-2014 02:03 PM

I would ask them what they are wanting to do or go with this tank as depending on how into it they are will make a huge difference on what they want or need in a stand.

Plywood on top mainly for dimensional stability and potentially look. Unless you are using a rimless tank all the weight is supported along the edges and no contact is made between the glass tank bottom to the top of the tank. A thin sheet is all that is needed for dimensional stability. Almost all the stands most DIY aquarium keepers build are overbuilt because well it doesn’t take much skill. It can be sloppy and easily still support a tank.

Based on the description of under the current tank it is in fact a sump. There may be a RO reservoir also but based on his description of salt likely the sump or they are just sloppy with water changes. I have absolutely zero salt residue under my tanks and clean every once in a blue moon because of dust. Properly plumbed tank, skimmer functioning properly, etc.. and all is good.

Rarely are backs placed on stands it makes the too air tight and circulation is needed and people get into trouble with mold. Some of that was do to older lighting technology and getting rid of heat from return pumps, skiimmers, power heads, etc.. was often needed or you were stuck running a chiller. Also always good to have gas exchange with the tank to avoid issues in reef tanks which is opposite of planted tanks as we are always trying to increase CO2 concentrations in the tank to induce better plant growth.

Anyone running a sump often ends up with a similar issue… not enough space. Get a sump, potentially RO reservoir, and all the goodies inside and depending on how techie they are monitoring equipment and it gets incredibly cramped. Some just end up placing the tank near garage wall or large closet so they can just end up setting all the equipment there and plumb through the wall to the tanks. Avoid the urge to “beef” something up that may not be needed as it just makes it difficult to do maintenance or replace things if needed. To get around this issue some end up making end panels that are friction fit or held in place by magnets so they can easily remove items. Few pictures (not mine) of sumps.

View Jim's profile


150 posts in 3828 days

#9 posted 01-28-2014 01:57 AM

Ok, one more question for you guys then:

If I’m going to attach the side walls of the cabinet to the base and top, using pocket screw joinery from side panel going into the top and bottom, with the already mentioned rusting issue should I get ahold of stainless pocket screws? I’m leaving the back open like mentioned, but I’d rather be safe than sorry. Trouble is, nobody around me sells them so I’d have to order them online.

As always, I truly appreciate your input guys.

-- -- Jim - Kokomo, Indiana

View dahenley's profile


136 posts in 2599 days

#10 posted 01-28-2014 03:17 AM

you can use epoxy coated screws.

my 240gal tank is made with single layered oak plywood with 3/4 face frame on front.
i have a 220 in the garage (the tank is made with 3/4” thick glass and it has single layer sides, 3/4 oak face frames and double layered cross pieces in the back. (no vertical support)

i would never use 2×4’s 2×6’s 4×4’s because most of the time they are not cured and dried all the way through and as they dry or age, they twist and crack and can cause problems.

If the tank is glass, then it has a plastic rim on the bottom and most likely top (won’t have one on top if its a rim less tank) but glass tanks sit on a plastic rim and they are supported by that plastic (which means there is no middle of the tank touching anything, so putting as much or as many layers of plywood on top will do nothing if there is no plastic touching it haha.

also, RR tanks (reef ready) have overflows. if its a standard Aqueon RR tank, then the overflow has 2 holes in it (one is a 1 3/4 hole and the other is a 1” i believe (thats to hold a 1” and 3/4” bulkhead) and those are very close to the back of the tank, so watch your support because it can inter fear with the plumbing)

the plumbing parts are thicker and bigger then the holes in the tank.

-- David Henley

View dahenley's profile


136 posts in 2599 days

#11 posted 01-28-2014 03:24 AM

heres the current 100 gal cube tank in the making

heres my current 240 gal (8’ long tank)

here is a 150gal tank stand i build for a friend. (it was a pensula tank so it can be seen on 3 sides and used as a room divider) its made from oak. (it was my first time making raised panel doors)

heres a 220gal tank (the tank is 36” tall and made from 3/4” glass) this tank actually weighs more then double what my 8’ 240 gal tank weighs) and its made using 3/4 plywood (single layer) and 3/4 face frame material.

-- David Henley

View Jim's profile


150 posts in 3828 days

#12 posted 01-28-2014 03:51 AM

Thanks again! I struggled with how to attach these sides for a bit because there’s overhang from the bottom and top platforms from the sides and I really didn’t want to rabbet into the top/bottom, and my friend did not want any 2×4 “box” skinned with plywood (can’t say I blame him). So after a bit of thinking, pocket hole joinery was my only solution (or am I wrong?) without getting into more complicated joinery options. If I do go with pocket hole, I think I’ll try using the Blue Kote screws. Kreg’s website lists them as 400% more rust resistant than the zinc ones. I’ll also have them plugged so I think they will be fine with the back now open. Might even put a dab of silicone in the holes if I’m really feeling anxious.

Thanks for looking out on the plumbing. I’ve already taken dimensions on their plumbing under the tank and will probably cut a 5”x5” hole in the rear corner to accommodate. We actually talked about the supports, he was concerned that I was going to have to put one in the center on the front of the tank. He was worried about having to fit the over flow tank in there. The cabinet is 48” long, and the tank is 30” long. I’m trying to manage without having a vertical support in the front but I’ll cross that bridge when I get there. For now, it’s double 3/4” top and bottom with single 3/4” ply for the sides. I’ll use 3/4” solid oak for the face. I’ve also laminated double 3/4” ply “pillars” for the back of the cabinet for support as well.

P.S. Nice starfish knobs!

-- -- Jim - Kokomo, Indiana

View dahenley's profile


136 posts in 2599 days

#13 posted 01-28-2014 04:13 AM

here is a picture of the supports i put under the 150. (it just has 4 sides (this tank had a center support so i added one) and i ended up putting a vertical support under the inner frame because the tank sat in that cradle and made it look built-in after i siliconed molding to the glass to make it seamless.

here you can see some of the extra support compared to that first picture.

also, you will note that there is no plywood because glass tanks (under a few hundred gallons) sit on plastic so having plywood in the middle does nothing…. so that tank sat on 4 sides and a center support (because thats the way the tank was engineered)

-- David Henley

View dahenley's profile


136 posts in 2599 days

#14 posted 01-28-2014 04:18 AM

heres the stand for the 100gal cube (no plywood)
and i used pocket screws and glue. no need for silicone. in that 240 gal, it was at a college for years and i have had it for 5 years and it has pocket screws with minor surface rust…. i have taken them in and out many times. and they are still holding so epoxy coated screws will be fine.

heres the bottom of a dirty tank. note the overflow holes and plastic rim.

heres the plastic rim. (note from where the stand is, there is almost 3/8-1/2” of clearance from where the glass tank sits and where the glass tank is. )

-- David Henley

View woodbutcherbynight's profile


5974 posts in 2915 days

#15 posted 01-28-2014 04:19 AM

TravisH that rig looks like something one might find in say the Space Station???? I never knew a fish tank and keeping the fish were so complicated, but then I thought you could fish with a grenade and it was legal. (Laughing)

-- Live to tell the stories, they sound better that way.

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