Why did you choose to go so high on the stand? (curious)
210 gallons is over a ton of water.. plus stand, rocks, and equipment.. is that part of the house sitting on foundation?
Also, it appears that all of the weight will be resting on the top frame of the stand, instead of the vertical beams. How did you attach these? If just nails/screws.. over time I think it will bend and cause you problems.
I have a 280 tank that I've wanted to set up but I won't yet because it sits over a crawl space and I'm scared my handyness (or lack thereof) would be off just enough to have a crashing tank and 280g of water flood my house.
Freaking beautiful stand, tank, and setup! Jealous