I have three hermit crabs, when I bought them they were all very tiny and one was slightly larger. After two months the larger one is three times the size when I got him. Ther other two have only gotten a little bigger than they were when I got them. Anyway. I have a 30 gallon tank, salinity 1.023, nitrate 20, nitrite 0, alkaline 300, ph level 8.4 . Everything looks great but my biggetst hermit has been climbing up my air tube and hanging by the silicone outside of the water for long periods of time. The other day it had to put him back in because I was afraid he would die. He is constantly going up and out, he cannot leave the tank because of the lid but Im worried about the thing. lol. Help! Im thinking of removing the air stone because of the research Ive been doing, but I kinda like the bubble and its not very big.