i haven't gotten one, i only have a thermostat. Its a whole block so its about 2 inch thick. Most of my thumb can bury.
BUT thats totally the problem , i didnt dry it before placing it in there because the directions didnt say. i only had him for 2weeks so this was my first Go-Round. Im abouta to make more block now and let it dry out.
Also i when i get paid ill buy hydrometer. Thank you both.