How much weight can the brace of a tank hold?

[kieran01pd2016]

Basically my tank looks exactly like this one. 1.2m x 30cm x 45cm.

Because I have the worlds most annoying cat, I was originally going to keep it lidless but he enjoys pawing at the water and, one day, I highly suspect he's going to fall in and make a mess.

I tried putting down a few sheets of 4mm glass, but because of how it sits on the braces, there are flex points in the middle of it wherein when the cat does walk on it, it bends just enough for me to worry about it snapping and shattering glass everywhere.
Right now, I've built a cover with 2x4 planks and some metal brackets. It totals to about 10-15kg and rests completely on the braces (doesn't touch the actual sides of the tank). I have a gap in the middle for the light and overall it does look pretty good - like a low profile lid. So far, it's been fine and doing the job. He does go up there (weighs around 4kg) and everything seems okay...

Does anyone know if what I've created is a terrible idea? Will it eventually break the tank?

Thanks in advance

 

[GaryE]

When I was in my teens, my mother's cat fell in the tank. She liked sitting on top, and an entire lid snapped one afternoon. She survived, but it is something to look up and see a cat swimming among the swordtails.
She wasn't a fat cat, and it wasn't thin glass.
There's no useful advice here except to say glass can have weak points, and your question is something to think about for cat keepers.

 

[MaloK]

2x4 planks and some metal brackets... 30 pounds... I want to see that !!

My cat once went directly flying in a 50g tank, because he was used to jump on top of it and didn't notice...

I had removed the cover to do maintenance...

 

[Magnum Man]

I use plate glass where I expect the covers to have to hold weight

 

[Fishmanic]

1/4 inch thick plexiglass would be stronger imho

 

[kieran01pd2016]

1/4 inch thick plexiglass would be stronger imho

I did give that a shot but the cat actually flexed the perplex a little more than I was comfortable with ...

 

[kieran01pd2016]

2x4 planks and some metal brackets... 30 pounds... I want to see that !!

My cat once went directly flying in a 50g tank, because he was used to jump on top of it and didn't notice...

I had removed the cover to do maintenance...

Gave it a proper weigh today... it's actually about 20lbs so not that heavy. Do you reckon that brace can take that weight plus an additional (occasional) 8lb cat?