Fertilizing a Masdevallia "Speckled Treasure"

[superstring]

Hi All, first post.

I recently took over the care of a Masd. "Speckled Treasure" from a young friend who wasn't having a lot of luck with it.

I re-potted it in a (predominantly) fir bark medium, trimming off the dead roots in the process. It's been doing relatively well, putting out three new healthy leaves so far. I water it every other day and (doing a bit of research) I found most advise fertilizing once or twice a month. What I don't know is whether this means fertilizing at "full strength" or diluted. In the meantime I've been fertilizing every two weeks with Schultz's Orchid Food (15-5-5) at the recommended concentration. However the "recommended concentration" is meant for "every time you water".

What do y'all think? Should I up the frequency of the Schultz or (maybe) switch to something else?

Thanks!