When I get those cheap pine black stands, I add 4 4x4 studs in the 4 corners, just to be sure. Also makes it more rigid. Everything is built really cheap with minimal material required, like the cars they make today. The pin stands rarely break, but if someone falls on one or leans on the tank, I can break. All the weight is vertical with no strength in the perpendicular dimension. I did however bend and put cracks in one under a 240 gallon frontosa tank. It's about 2400 lbs given water weighs 8.3 per gallon, plus the tank and rocks, so I added huge studs and 2 4x4 in the middle of the stand, to take weight off the center of the tank. The bottom glass is tempered glass, but having no center bracing adds more weight on the tank corners. When I change the water on my 240, i can hear the wood stretching and popping. 75 gallon tanks are fine, ive got several, but anything larger, I would be careful on the stand. It's kinda like a semi truck, the more axles you have, the more weight is distributed along the length. Less damage to the floor boards, and less push on the glass, for large tank for example. Tanks over 150 gallons have crashed through apartment floors, and thats a fact!