The coris wrasse is a great suggestion. I would just add the recommendation to stick to the Yellow Coris Wrasse rather than the Red Coris Wrasse. The Red one gets very very big and as a result has a much higher likelihood of going after your inverts. The Yellow Coris ten to remain much smaller and and less destructive :-)

Another suggestion along the same lines is a Green Wrasse. They look just like Yellow Coris wrasse, except green :-)

A small Melanarus wrasse might be okay but unfortunately I think they are one of those 50/50 chance fish. They may go after your inverts, they may not. I've heard plenty of reports from both. The other thing about the Melanarus is that they do tend to grow pretty big also. I got mine at about 3 inches and now he's 5 almost 6 inches!

I did some searching and as nivlem09 said, velvet nudibranch will eat flatworms. But thats all they eat so you would have to pass him on when they are all gone.
Will help if you feed less. Everytiime you chg water, try to suck them out. That will help the most right away.

Thanks all. Yes they are the photosynthetic ones. I have been siphoning them out but they just keep on coming. I target feed my corals and crabs once or twice a week.
For flow I have a Korilia 1 and 2 in my 28 gallon long (I think I said it was a 29 before oops).

The wrasses intrigue me but I worry about their invert eating habits. Velvet nudi is cool but once the flatworms are gone then they have no food source. :(
I will research a bunch of your suggestions now as there were quite a few.

Thank you again all.

Ive used flatworm exit a few times on tanks ive had if you follow the directions it works good and ive had zero issues with fish or coral stress