What plywood thickness do I need to help support my aquaria?

[saintabyssal]

I've been planning a rack of aquaria for a while now. I'm going to use a Uline widespan wire rack with wood laid over the shelves to better distribute the weight. My original plan involved large tanks supported by sections of "two by" lumber laid across the rack. Since then, I've revised my plans to use smaller tanks as pictured in the diagram below. I was hoping to be able to use thinner wood, like plywood to give me some more head room in the shelves, but I don't know how thin I can go before it's too weak to support the tanks. What thickness should I go with? Or do I need to stick with the original "two by" plan?

 

[kansas]

Your heaviest shelf is the one with the 4 15 gallon tanks, maybe 600 pounds. I see the shelves you're using are rated at 1400 pounds each, so thin plywood would be fine,

I'd put a yoga pad under the tanks in case of any uneven spots on the wood.

 

[briangcc1997]

I would go 3x4" BCX exterior plywood. Do not get pressure treated as the chemicals will react with the metal and eat it.

You do know you could do that with 2x4's for a lot cheaper than $275 plus tax/shipping right?

 

[Sewerrat]

Would personally use 1/2 plywood at a minimum

 

[Fishfur]

I have 3/4” plywood on top of one of those square tube all-steel open frame stands. The stand is 5’ long & 18” wide and supports a 31G + a 20G high on top plus a tiny long tank in front of the 20 (which might weigh all of 30 pounds).

The total weight is likely somewhere in the neighbourhood of 700 pounds with the rocks, wood, water & equipment.

The bottom supports a 29g also on 3/4” ply.

The plywood on my stand is supporting this weight by itself because unlike your shelves, it only has support around its edges (since the stand has an open centre).

I’d be surprised if you needed more than 1/2”thickness plywood when its function is only to spread the weight more evenly & make a nice smooth surface, rather than literally supporting all the weight by itself. You might even get away with 3/8” plywood.