In case anyone is interested...
Just treat my tank tonight. No ill effect on anything but the red flatworms. Pods, snails, fish, corals, anemones, brittle worms, etc. all didn't show any signs of stress. Couldn't find the same brand/form of levasole as described from reefcentral. Ended up just added a little at a time till red flatworms started to died off. I only kept the skimmer off for about an hour and now the skimmates have a red hue.