Thank you. This comforts me a lot.Ime, the tank bottom will conform to the stand when its filled. All tanks, especially glass tanks, seem to flex at least a little bit between empty and full. The old 150 i have, with 5/8" bottom, seems to bow upwards nearly an inch in the middle when i empty it, but will settle into any flat surface once its at least half full. Scared me a bit when i first got it but now i think nothing of it.
In short i think your bedding compound may be unnecessary given the flatness of your stand and its unlikeliness to move at all, being so sturdy and well rooted.
This is the biggest glass tank I've ever filled by over double my current 55 gallon.
I've played around with different tanks on different stands, and I measured how they deform when they are full. The 55 did not really deform that much, though there was a little bowing and bagging.
The thirty standard was the worst and the 30 talls barely deform at all.
I have no doubt that the glass can take the stress because I have tested large glass windows and blow them to Smithereens with air pressure. My biggest concern is that stresses will develop in the silicone vertical joints, and it will start seeping in 10 years when I'm too old to fix it.
It seemed to me that when I looked at the commercially made 125 stand it only supported the tank on the ends and in the very middle and it basically sat on three pieces of one by four. Each point of support was only approximately 1.75 sq inches. When their literature says I must have a properly designed stand, it seems like this tank only requires 6 equal points of support.
If this 125 blows I'm going to end up buying new furniture and new carpet at least. While I could afford to do that without a lot of pain, what would cause me pain is the look on my wife's face as she says, "I told you that tank was too big!"