Hrmz, many reefers avocate against leaning anything on the tank walls....reducing pressure on the walls, preventing the walls from getting scratched....but i dun see any problem in using your tank wall to give your LR better support....as long as it doesnt bear its full weight on the tank wall, i think its pretty safe....i only lean my LRs on the back panel though, so i can clean the other 3 sides easier.....try leave a gap, big enough to do some work.