Ken: Sounds like there was still something under the Poli Glow trying to leech out from the gelcoat. The Poli Prep will also remove the Poli Glow and thus what is below it. Think of it as a clearcoat for gelcoat. The clenz all you mentioned is in reality powdered oxalic acid and would have removed the Poli Glow as well! I recommend trying Poli Prep first, so you did the right thing! Dan