nitrates are driving me up the wall

[Myka]

What brand of test kit? How old is it or when is the "best before date"? What kind of skimmer? How long has this tank been setup? How old is the live rock? what the live rock bought from a previously setup tank? Is it all live rock or was some of it dry base rock? Do you run GFO? If so, what brand, how much, and how often do you change it out? If not, consider adding one in a reactor and use any of the brown GFOs, not the white kind.

It will help if you replace half the feedings with flake or pellet instead of frozen foods as they are loaded with phosphates and nitrates. The "purple diatoms" is probably cyanobacteria, not an algae. Both diatoms and cyano are caused by excess nutrients.

What kind of corals do you have? Consider skipping out on the Reef Roids until your parameters are back under control.