Base for Fish tank

[upnorthal]

Hi

I'm after some advice as I appear to be getting a lot of conflicting advice from builders.

I want to build a base to house a marine fish tank on 5 foot length, 3 foot wide and 18inches height.

The plan is to build a couple of pillars at opposite ends and run three 127 RSJ's along the length (resting on the pillars).
On top of the RSJ's I will place a decent cut of marine grade ply wood as a base for the tank.

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The drawing is not to scale and the brick work will not necessarily follow that pattern.

I'm planning on using dense concrete blocks to build the pillars. Space is a premium underneath the cabinet (as a variety of filtration equipment has to be stored).

The plan also is to have a third wall running along a length. (not shown in sketch). - so in effect, it will be three sided concrete block base.

On to my question...
Can I build the pillars so they are 100mm wide and 440mm tall concrete block?
One of the end pillars will be butted up against a house wall, the other pillar will be free standing so to speak (apart from connected to the wall that will run the length).

I've been told by some people that the stablility of blocks on their side could cause a major problem.

PS. total load estimated to be one tonne.

 

[Static]

So basically the size of a bath.. why not support it on timber (easier to build and lighter weight)?

 

[upnorthal]

Hi

Timber would have been ideal had it not been a fish tank I am supporting.

The problem with timber is the wood can shrink and expand. If a tank base goes out by a couple of mm, this can
cause significant stress on glass tank seems - I'll leave the rest to your imagination!


Cheers

Al

 

[big-all]

your only talking surface friction this will have no effect on a smooth glass surface
if you use ply it will not move except up to 1mm around the edges

 

[upnorthal]

Sorry, I should have mentioned the tank has a floating base.

What this means is the glass bottom of the rectangle shaped tank is in effect two squares siliconed together.
(it actually costs more to have tanks built like this, but it is an additional safety measure as there is a little more 'give' on the base when you are loading the tank with rocks etc.

Around the premitter underside of the tank are 1cm strips of plywood.

So, the tank bottom surface area never touches the cabinet. Its the plywood strips around the edges that take the load.

Do you think that makes a difference?

 

[freddiemercurystwin]

Surely advice from the tank manufacturer would be best? They'll surely have fairly strict recommendations if this kind of thing is an issue?

 

[Static]

Also what kind of flooring is this tank going onto? I would assume a ground concrete floor, but best to check..

 

[upnorthal]

The floor is concrete in my lounge, so that should be able to take the load.