your question is very valid,
you should be fine with that set up especially due to the fact there is a load bearing wall below the tank area
But I would still use the plywood sheet underneath the tank to distribute the weight evenly
I have a few tanks myself lol;-)
I will stick with you until the unit is fixed properly.
But please rate my service thus far to you before closing this page.
It won't cost you anything to further to rate and I will be with you at no additional cost until you have this repair complete;-)
I dont see any response from you so I will switch us to Q & A, you can respond there to me;-)
Thanks for the answer but did I make it clear that it's 500kg not pounds and that the tank won't be above the load bearing wall but next to the wall that's on it?
I'm sure you can understand my nervousness!