These type questions should be asked on the regular forum.
You will get many different answers.
I was just asked this question in a PM.

"what do you have in your albis,savs,argus tanks as substrate....how deep is it?"

I will answer it like this. I use what works for me and my critters, I am not going to say it will work for everyones.
With my albigs I use plain old dirt from my back yard mixed with many, many buckets of dirt from the river bank.
Unless you live in the same location as I do, this might, or might not work for you.
For my savs, I use a somewhat sandy dark, almost black dirt from the local sandand gravel place.
I don't know what it is called. It works so I use it. I pay $6 a ton if I load and haul it myself.
With my albig I am using a lighter, sandier dirt from the same place I get the sav dirt. Same price.
I went through many different substrates before I found out what "They" (the lizards) were happy with and used.
I am sure I will try different substrates with the argus since it is my newest critter and it doesn't seem to be too picky.
All it wants is something it can dig in and fill the water bowl with dayly. I am thinking it likes mud.
All my cages are between 1 and 3 feet deep with substrate, depending on where they throw it.
I am sure to have to try differnt ones with the albigs and the savs if they won't nest in what I give them.
Everyone else is more than welcome to answer this question so the person that asked me can be more confused.Hahaha

Scott
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Do not meddle in the affairs of dragons, for you are crunchy and taste good with ketchup.