There is no problem there if the tank stays that way as you fill it. The only problem would be if it starts lean anymore one way or another. My guess though is that as you fill it the carpet will be compressed and the tank will level out even more as the concrete slab underneath takes more effect. My 125gallon was more off than that before I filled it so I just paid attention as I filled it. Now, after filling it and running for over 5 months, it is almost perfectly level. I checked it almost every week for the first month but nothing changed. Hadn't checked it in a while but thought I might as well since seeing this. Again, nothing has changed. So just pay attention to the level as you fill it and you should be fine.