Leveled the tank last weekend, I never want to go through this again!
I used 4 air-shims, which are inflatable air bags, to lift up the tank + cabinet. Each was rated for 300lbs max.
There are my approximate weight calculations:
700lbs - Cabinet + DT + Sump (e-mailed red sea to ask, it ships 770lbs with crate, crate weighs around 70lbs)
100lbs - Sand
400lbs - Misc weight of undrained water/wet sand/equipment (this number is overestimated on purpose, probably by 300lbs)
Total weight comes to about 1200lbs.
Initial force needed to lift one side should be half the total weight, so I needed to lift 600lbs with my 4x300lb shims.
The air shims slide right under, fits perfectly between the Reefer's rubber legs.
Air bags are slowly pumped up by hand, was super easy.
My tank was leaning forward + to the left. I used superglued coins as my shims, allowing me to gradually change the elevation from left to right and front to back. In the end, I managed to prop up my front left corner to be pretty much level with my back right corner. It used to have a very noticeable difference of 1/2 an inch.
The whole process of emptying, shimming and filling took about 3 hours to do. Luckily there wasn't any livestock losses, but I'm sure they were super stressed.
Like humpty dumpty, I couldn't put all the rocks back the way it was, so the rockscape changed a bit, which ended up pretty cool. Some corals came off, and I will be re-attaching them this coming weekend. Will do an update of the tank soon!