I am upgrading my gecko and i need a better substrate than paper towels
What type of gecko? Leopard, crested, etc. Also what type of enclosure? What do you feed? How do you feed? Are you in a dry or wet climate? And so forth and so on.
There are a lot of different substrates that will work depending on the answers to the above questions. I have a leopard gecko that eats large crickets from tongs so there is no chance of her ingesting substrate so I use cypress mulch.
For leopard geckos I think paper towel or tile works best. My leos all have pretty big habitats with paper towel (I use recycled brown paper towel). My geckos range in age from ~2.5 to just under 20 years, and some are special needs.
The only reason to use a loose substrate would be if you are going to go bioactive, otherwise it’s too much risk for something merely cosmetic. Bioactive enclosures are very pretty and can work well if designed and maintained properly, but are generally very ill-suited to older leopard geckos. Probably any leo over ~15 years old should be on a mostly flat, non-particulate substrate. Always choose any invertebrate cleaning crew carefully to avoid protein-hungry species when housing with leopard geckos. Hungry insects can mortally wound sleeping geckos.
Coco fibre, orchid bark, moss etc. my fat tails are in bioactive also.
For my Leos, I got away with using dry coconut fiber. They hated the taste so if they got a mouthful it was spat out immediately after.
I have used larger flat slate like or round river stones before with a light dust of sand between them for a display tank… but that was only after careful monitoring. I had one male who just insisted on shoveling sand in his mouth, even with a constant dish or calcium and a vitamin one, so he was never put on anything but paper towels.
As was mentioned by @mblaney , there can be risk with any type of loose substrate
Anything you put in should be large enough that it cannot be swallowed or monitored very closely for the gecko potentially eating it.
Do not use crushed walnut bedding as it can have sharp edges that can injure them internally if they eat it.
Always make sure you are providing the proper vitamin supplements as well because that will help keep the geckos from munching substrate as well (unless they’re like my one male)