Can anyone tell what type of gunge/slime is used to fill the pool with? Is it Natrosol? Methyl? Something else? It's exactly the consistency and opacity I have been looking for but can't quite seem to find.
Can't tell you specifically, but you can get that consistency with a number of cellulose variants including HEC, methyl, xanthan, guar, plus starches like corn starch. HEC is probably the easiest. As far as opacity, all of those cellulose variants form translucent gels, the opacity is a result of what pigment is used and how much. Also lighting and clothing have an impact on perceived opacity. As for that very specific opacity and thickness, you can probably get in the ballpark by mixing dark blue "thick" gunge from Messy Supplies or Splat Emporium with uncolored or "glass effect" gunge to increase the translucency a bit.
If you're making the gunge from scratch, you're probably looking at around a 1 to 1.5% solution to get that viscosity. Try small batches to see what solution gets you the viscosity you want and then from there you can just add as much pigment as you want to achieve whatever opacity you want.
There are a lot of videos on YouTube demonstrating cellulose gels at different viscosities: https://youtu.be/sC3Dfka-Ywg
Love you, too
