I have only had my ASF's for 9 weeks and they haven't bred yet, so all i can do is regurgitate what i've read here.

A lot of people talk about 1.3 as being standard. 1.6 is for people who need more. And somewhere i read a guy was doing 1.20. So i'll agree with Deb and say figure out what you need, then go from there. The ASF caresheet is a great place to get some good info.

My one piece of personal advice, research first and know what you are buying. I am almost convinced that my 1.2 has become 3.0. if my last rat drops some nads and i have three males, i am gonna lose it on the guy that i bought them from. It's my fault, they were young and i didn't know how to sex them.

good luck