Cinder Block Stand, did I screw it up or is there a way?

[Levinson]

I've just built a cinder block aquarium stand for 20g tank yesterday and I think I may have screwed it up.
I've got four 190 * 100 * 390 blocks (7.5 * 4 * 15 approx in inches) to have 2 stacked on each side, with 2 by 4 pieces sitting on top,
After building it, I realized that the width of the block (100mm or 4 inches) might be too narrow. I'm worried about the possibility of it collapsing with a push from the sideways I can't imagine what it would be like with the tank on top (I don't have a tank yet). Would it make it top-heavy and make it less stable or would the weight pressing on it make it more stable?
Did I just waste money with the cinder blocks? Is there a way to somehow make it work with the current setup or do I need new/more stuff to reinforce it? What should I do?

Some of the solutions I can think of right now are:
1. Ask for advice in R2R
2. Get the wider cinder blocks (150mm / 6in) and replace the current ones, accept that I've been stupid and wasted money)
3. Stack the blocks sideways and sacrifice the height (or get more blocks to stack up), also sacrifice the space under the tank stand.
4. Epoxy something (dunno, a piece of wood or something) at the inner bottom side of the cinder block to widen the bottom.
5. Get 2 more of the same cinder blocks and stack them at the mid-back, place more wood on top, then go for a bigger tank! (a wider 30g tank)
6. Think of a way to build some s#it to support it somehow
7. Just go with it and hope it'll be alright

Some additional info:
- There are only two cinder block sizes that I can get locally: 190 * 100 * 390 blocks (7.5 * 4 * 15 approx in inches) or 190 * 150 * 390 blocks (7.5 * 6 * 15 approx in inches)
- The bluish paddings are yoga mat that I cut up (for levelling, cushion etc). The top piece is where the tank will sit.
- I've had the 2 by 4 cut a bit longer than needed so there's little extra room to be used (10cm or 5in longer than the tank I was planning to get)
- I've filled the cinder block holes with some pvc pipes that I'm not using
- The yellow stuff on the right is just some snack for me to munch on time to time, there used to be double that amount.

 

[Brad_95]

You could use a cement adhesive in the seams between the cinderblocks in order to secure the vertical movement, and as far as fixing the potential toppling, you could do an L-Support bracket and drill it into two of the wood boards and cinderblocks at that right angle. That’ll take out any horizontal movement.

 

[Brad_95]

Something like this. It’s cheap and it’ll keep it still.

 

[JR Bodyman]

You can change to the bigger type of blocks like these. They are cheap and with the weight of the tank it will be very stable.

 

[mann1139]

A 20g isn't that much weight. It could easily be supported by most tables.

I don't know if there is any adhesive I would trust to keep a tank upright. If someone bumped the tank from the side, there is nothing keeping the entire setup from collapsing.

 

[theatrus]

> Would it make it top-heavy and make it less stable or would the weight pressing on it make it more stable?

More stable, assuming you aren't in an earthquake zone. If you are, anchor the top board to a wall stud.

> Did I just waste money with the cinder blocks?

Probably. Most tables can support a 20g just fine (its only 200lbs, static load).

> Is there a way to somehow make it work with the current setup or do I need new/more stuff to reinforce it? What should I do?

Whatever makes you happy. Its not even worth trying to calculate, but the downward force from gravity of 200lbs on top of the cinder blocks will be quite a lot, and require a very deliberate action to shift the blocks in any way. Earthquakes can set up enough movement that this is a problem of course.

 

[PicassoClown04]

It’s true about the table. This is just an ikea desk I stained and here’s our planted shrimp tank (10 gallons). I kept a 20 gallon SW tank on my dresser during college, so it’s really not a big deal plus a cheap desk from IKEA drilled can give you room for a sump underneath, water change water storage, ATO, refugium, all of that chilling under the desk so it’s easy access but all contained within the display and stand. IMO, a desk is the best choice for a stand for a tank that’s 30 gallons or less, just looks nicer and has everything you need from a stand without the crazy prices. Also, drawers for all the knickknacks you’ll need

 

[mann1139]

Its not even worth trying to calculate, but the downward force from gravity of 200lbs on top of the cinder blocks will be quite a lot, and require a very deliberate action to shift the blocks in any way.

I disagree. Without the cinderblocks being 'bonded' together, they will not resist movement, so leaning up against the tank could cause a 'wobble'.

 

[LeftyReefer]

Loctite makes a glue/adhesive for stone/rock/landscaping block that would work between blocks to tie them together.
Loctite PL-500. whole caulk tube of it for about $5.

 

[Levinson]

Thank you all for your ideas. In the end I decided to go for the bigger (wider) blocks. I've managed to return the blocks to the seller and change them to the bigger ones by paying the difference. Good thing I gave it a shot cuz I didn't think they'd let me.
I haven't set the tank stand up yet. The blocks got wet in the rain so I'm just waiting for them to dry. Just by the looks of the blocks, I think the stand is going to be alright. We'll see when it's done.
I know all this might be too much for a mere 20g tank but this was the cheapest option(cheaper than getting a table) and I could still use these if I ever change to a bigger tank in the future.

Initially, I was going to place some rubberish kinda floor padding under the tank stand to protect the floor from the minor water spills (cover the area much bigger than the actual tank stand, bigger than the size shown in the pic below, enough to gives some area for me to work on). But I think I might ditch the idea. I read that any waterproof padding under the tank stand will trap the moisture and the moisture will find it's way under it somehow.
I wonder though if it might be ok with padding/mat that covers much bigger area so all spills will fall on top of the padding/mat. Would you do it?
Just so you know, the floor is real wood, the mat isn't.

 

[Levinson]

Set the new blocks just now. Feels solid.