Feeders are like anything else. If you have the knowledge to know how to use them effectively, they can be very useful. if you don't, you get a mess.

While we normally recommend bleach solely as your chlorinator, there are clearly times when Tri-chlor tabs, Di-chlor powder, or Calcium Hypochlorite are appropriate, or easier. When I want to raise my CYA, I start chlorinating with Di-chlor, until I'm close to my target.