I have a 55g metal stand with two 20 gallon stands on the bottom, and nothing on top. I'm wondering if the top of it will be strong enough to hold up two 20g or two 25g with substrate, and driftwood or will the top bow down in the middle?

If it was built to hold a 55 on top I don't see why it wouldn't support 2 20 gal .

cool, I just wanted to make sure because I don't want to wake up to a crash with broken glass and water and rocks on the floor.

no worries, if it's a fish stand

THANKS and yes it's a fish tank, it's the one I got from a member on here.
looks like I got some work to do.

NO
It works fine for one tank but if you have 2 tanks side by side the stand will bow just a touch and press the tops of the 2 tanks together.... That very well could cause a stress fracture and a very big mess.

rats, so I should put a 55 on there? or just build a 2x4 stand and paint it black?

I wouldn't risk it....

I agree With Fern, to much pressure on the top edges of the two tanks, wont be a good picture.

okay, Thanks I won't risk it then... any one need a 55g metal stand?

um will my plants, and fish be okay in a bucket. if I put the plants in one bucket, and the fish in the other with a seeded sponge filter, and heater?.............. long enough to take them off the bottom and put them on a 20g metal stand and set them back up?

and I will use the aquarium water in the buckets, so I don't kill off the sponge filter, and then use the aquarium water back in to the tanks....

Thanks.