Substrate Question

Right now I have my ball in a 10 gal tank with paper towels as substrate. I plan on putting him in a tub when he gets bigger. Now if I stick with paper towels in tub do I put the probe for the Digital Thermometer and Hydrometer in between the the paper towels? Would it be better to use eco earth the one that comes in the brick as substrate?

Thanks

Yes, if you are going to continue to use papertowels, you would place it on the plastic of the tub, right below the papertowels. The only reason you should switch to ecoearth is if you want something that is nice to look at. However I would steer clear of Ecoearth, its a huge pain to clean up.