On another note;
Even if the "Can I Mash it" calculator says you could get 92lbs of Grain in your 10 Gallon Igloo with .5qts/lb water what it won't tell you is
Can you sparge it?
Even 30lbs of grain is a lot of weight held in a tight column. Think about your false bottom, braid, or whatever you have in the bottom of the tun for wort collection and the effect of all that weight on it.
Will it collapse under the weight and heat?
I have had a dome stainless steel false bottom collapse under the weight of 30 pounds of grain in a Keggle. It ain't fun, let me tell ya'.
So, consider whether or not you can get any runnings from that much grain in your system because there is nothing worse than looking down onto 30 pounds of converted grain and not being able to get the wort out.