Tank NOT Level in New House

snoopy..have you or your husband maintained any tanks on concrete block stands...?

If it moves because you walk around it..it isn't the blocks..its the framing in the house....
 
Aquariums, no but my husband has worked in construction since he was a kid and is 44 now. He set up mobile homes for 14 of those years using concrete blocks. He says because of all of his experience with those blocks he wouldn't trust using them as far as I could throw one. Which isn't very far. It has something to do with the integrity of the block itself.
 
As an aside, cinder blocks are super strong, just make sure they are oriented properly. I'm sure 99% of you know this, but a cinder block loses 70% of it's strength if used improperly. Just puttin it out there for the inexperienced, not trying to insinuate.
 
thanks, everyone for the ideas.

In our old place, I used the same setup with the tank, but it was on a wood floor over slab, and it never moved. And was the perfect, low cost, low effort, strong, and stable base.

Here in the new place, however, it's over a basement, and the floor joists are metal with some type of fiber board on top as a subfloor. I have no frame of reference for how strong this floor is, but I'm thinking that it will be as strong or stronger than wood. I sure hope I'm not wrong.

There is some wiggle/bounce if you stomp next to the tank, and I figured it was just the carpeting and would compress over time, but because of the comment about the floor sagging, I'm wondering a whole bunch of things... I know that i'm adding additional weight (about 600 pounds or so) to the equation by using cinders as support and that concerns me a little too.
 
I don't like the sound of this at all. The 800lbs of water + substrate + the tank + the cinder blocks all focused on three small area of floor is not good.

How far apart are those steel joists? If those cinderblocks are not lined up with the joists you are putting a heck of a lot of weight on the flooring. Which way do the joist run in relation to the tank? If the tank and joist are not perpendicular then you will have to move your tank.

The basement sounds like a stellar location for it. Straight on the cement floor.
 
I don't like the sound of this at all. The 800lbs of water + substrate + the tank + the cinder blocks all focused on three small area of floor is not good.
You make another very good and important point that 1600+ pounds distributed over 3 not 4 detached independent legs, is about 500 Lbs per square foot not to mention that 3 legs is not exactly the most stable platform, sound like one person falling against the tank with drink in hand would send it on a teeter to the floor. The full footprint of a good stand with a full base would disperse the wight so much better it would amount to only 90 Lbs per square foot and because the base would even out the differences in unevenness and share support, no shimming at all would be required.

But other then that it should be fine provided Murphy's law stays out of the equation, "Anything that can go wrong will go wrong."
 
You want to know which way the floor joists are running and position your tank across several, rather than along a single joist. This way the tank won't tend to tip forward or backward.

Trashman has a point. To put it in my own words you can put a house straight down on them and they won't compress, but use them incorrectly and they can pull apart. That is the nature of cement.
 
Cinder blocks are rare. Most blocks are made of concrete mix. They are a lot stronger than people give them credit for. I worked at a block plant for a couple of years and learned how they are made and tested for strength. There is also a waterproof version as well as insulated versions. The argument of not being a good source of vertical strength would mean any house or building using them for load-bearing walls would collapse under the weight of a roof. That argument is simply false. It would also mean that they would not be able to support the rows above them and again that is false. When they are laid on a firm surface, they are more than strong enough to support the weight of an aquarium. As far as being unevenly made, the variance allowed during the manufacture of them is a very close tolerance, not perfect but not a vast difference. Blocks made during a single shift are likely to be the exact same height produced during that shift due to the machine setup and aggregate mix. Blocks that are of different height, etc are pulled before they can be sold to the public. They are then sold as blems or sold as fill. They are not sold as construction stock. They have to pass strength and quality tests as prescribed by your state building codes.

I would not use lightweight blocks as they have a high pumice content and are only for non load-bearing walls.
 
Well the truth is when it comes to load bearing construction and use of hollow block, what they are made of is given very little consideration whether they are made of cinder, sand or styrofoam. Yes that's right Styrofoam, becasue they were never intended to be load bearing unless they are filled and reinforced with steel. So yes if you join and reinforce those legs with rebar and fill the cavities with concrete as intended you will not have a issue with the block cracking, shifting or tilting.

But of course that impractical and beside we are talking about the integrity of the flooring as well. make sure you check your home owners insurance policy for liability and damage cause by this type of speculative situation which could cause speculation by an insurance adjuster or lawyer in the event of property damage or bodily injury of a guest. Just a recomendation
 
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