That fertilizer will be just fine to use on all of your orchids. Normally I would use it at the rate of one half teaspoon per gallon of water.
So as an example if you had a little one quart watering can, you know those cute little ones from a garden center or hardware store, you would use like an eighth of a tsp. Not very much at all. Fertilize once a month should be more than enough.
If that seems like a lot of trouble for a single orchid, you could get Dynamite, which is a slow release fertilizer, and use it on all your plants both inside and out. I use the 13-13-13 formulation on my tropicals, my New Guinea Impatiens and my orchids here in Florida. I reapply every three months. Just sprinkle a half a teaspoon on top of the media that your orchid is growing in. Choose whichever option works best for you!
