I have been brewing kombucha for two years now, using children of the original SCOBY I started with. They typically ferment in a week and taste great. The only problem is my SCOBYs are very thin. I see online people using fat, 1/2 to 1 inch thick SCOBYs while mine are 1/8 or 1/4 in thick. So, are thin SCOBYs the sign of something wrong, and how do I fatten up mine?