campden or bentonite

I just did the first racking of red into 5 gallon carboys with airlocks on. When should i use the campden tablets and/or bentonite. I will probably rack 2 or 3 more times before botlling (or leaving it in the carboys until i bottle)

second question, have white wine in the carboys with airlocks, fermentation is slowing down, again when should I use campden tablets and/or bentonite. Thank you GREAT SITE

I don't usually use bentonite or other clarifiers, but I thought bentonite went in the primary with the must.

I use campden tablets at the crush (without a press, sigh) or, when I make country wines, at the mixing of the must. Also, at every other racking. If you have an so2 meter, you'd want to keep 50 ppm in the must/wine. I approximate that as near as I can by using one crushed campden tablet per gallon at every other racking and at bottling. I rack whenever I have lees 1/4 thick, or any lees at 45-60 day intervals.

Hope that helps!