Did you cut the three part down?? You should of cut your 3 part down to where the FF added would bring the PPM to the same level as it was with the three part. If you didn't that is probably why you burned them.
Example, PPM before FF with the 3 part, 1500, should have dropped the 3 part down to 1300 and then added the FF at 200 PPM to bring you back up to the 1500. I know in my case the Skunk number 1 are big eaters, always out eat anything I have going with them, but I have herd that the H is very picky, kind of like the Blue Barry.
Well, keep your head up.
Adieu