Monitors only need arid soils. I have seen good soil types in every state but Iowa(black soil) but I am sure its there somewhere. Its the stuff the farmers do not use, not good enough for crops.(which makes it safe for all the bad stuff they spray on crops we "eat"
DG, sucks but not as bad as other soils and not as good as many soils. That soil may work, but there are far better.
Also the title indicates to dig, monitors will dig in anything. heck even saw dust. That is not what its really needed for.
Heck again, you can raise and keep monitors on paper towels, the monitors do not like it, nor can they nest in it. But you can do it. The point is, giving them something they understand, and its outside nearly everywhere.
If you live in one of the rare areas where suitable soils are not available, then maybe your better off picking a species thats requirements that does not require particular soil. Like timors or many of the indo species.
In my experience, there are two basic substrate types, one for burrowing monitors(arid land species), poor draining soils. And one for Mesic/wetland/forest dwellers, which is leaflitter.
If you live where good aridland soils are not available, then surely you live where theres lots of leaflitter.
While it VERY easy for me to get desert soils, I live in the desert, its very difficult for me to get leaflitter, I have to drive about 100 miles.
So, I have mostly burrowing monitors, and a few forest monitors.
Please understand, that is not a very hard decision to make and it should be amoung the first you make. What species are you suited to keep. Then keep them properly.
Why that product is of no use. I do not care if its perfect for ackies. The amoung you need for either proper burrowing or proper nesting is at least 250 to 300 pounds. Now consider how much would it cost to SHIP that much, muchless buy it and ship it. Cheers