Ah yes. The old GAF tanks -- I remember them fondly. They were very easy to load and did indeed come with a thermometer / agitator. Once the agitator got lost (they always do) you are left with the slide it back and forth method or the twirl it method. These both work fine for 35mm but, I suspect that you'll slop liquids when doing 120...Guess you have to try it. I too eventually switched to Paterson.