New tank ready

[Tim Boulton]

Ok my new tank is now ready, but I've got some questions about the stand......The tank is 560 liters so the ensemble will probably weigh more than 600 kilos (1200 lbs). A mate has welded a steel frame together out of 1 inch square section steel and the feet are adjustable but only 1 inch diameter which, I think is too small for the floor loading. So, I plan to use 18mm mdf around the frame top, sides back and bottom to spread the load evenly and make a nice storage space too, only the floor is of quarry tiles and isn't flat, so maybe I should put polystyrene tiles on the floor first?
will it be strong enough? should I screw the feet out once the box is made to pretention the wood or is this a bad idea?

[AngelMom]

I guess the first question that needs to be answered is, do you know what the condition of your subfloor is (assuming it is wood and not concrete slab) and what is between the tiles and the subfloor (cement, wonderboard, etc)? If you have a wood subfloor, it would be worth the effort to get underneath and check the condition of the joists.

I'm guessing that your setup is going to be more like 1500 lbs (about 680 kilos) when you factor in the weight of the tank, substrate and stand. With only 4 feet, you will be supporting about 375 lbs (170 kilos) per foot, with each foot having only about 3/4" of surface area.

I don't think adding mdf around the steel supports will help to spread the load. What may happen is that the feet will compress the mdf in the four spots where they sit and may distort the rest of the "wood" and you will still have the same issue. If you take a look at wood cabinets designed for tanks, they use hardwood sides which go all the way to the floor to get the load distribution.

I think you will need to have a steel footprint at the floor that mirrors the part the tank is setting on to be able to get any load distribution. Of course, if you can't get it to lay flat (as you have stated the tiles are not of equal heights) that can be a problem.

What if you were to have your friend weld on extra feet between the four you already have? If you have a bottom support the same dimensions as what is directly under the tank, you could weld on an extra couple of feet front & back and maybe one extra on each side. That would give you ten feet, and will drop the load at eact foot to only 150 lbs (68 kilos).

You could then make a cabinet out of any material around the steel frame to store your supplies.

[Tim Boulton]

As far as I can tell it's a concrete subfloor, about a foot thick. I did look at existing designs before making mine; the mdf top and bottom are larger than the steel frame (as is the aquarium) to take into account the thickness of the side panels; the top and bottom slabs of mdf are 134x64 cm whereas the frame is 130x60cm the idea is to use the steel to provide support along the front length of the tank and the sides and back mdf plates to provide better load distribution to the bottom mdf plate and from there to the floor.

[AngelMom]

A concrete floor, while actually better for your home, will be worse for the frame & tank as it will not "give" if the feet try to shift on the mdf base. Basically, the feet will continue to compress the mdf until it can't compress any more. Unfortunately, it most likely will not do so evenly and may affect the stand or the tank (ie, try to warp them too).

BTW, I have verified that adding the mdf under the steel will not do anything significant as far as load distribution. You really should consider adding more feet to support the tank, especially since the floor you are sitting on is uneven. Load distribution is through the points contacting the base (or floor) the frame is sitting on (in your case, 4 feet). The only way to further distribute the load is to have more "points" contacting the floor (or base).

Also, one thing I forgot to mention in the last post.......I'm assuming you have used structural (grade A36 or equivalent) steel? Most carbon and stainless steels require heat treating after welding to recover the desired mechanical properties - structural steel does not.

Back to the floor though.......since you most likely have a concrete subfloor, the load distribution thing would be irrelevant as the concrete will withstand much higher "point" loads than will a wooden subfloor. With the uneven tile though, I'd still suggest you not put any mdf under the feet.