Keith, keep in mind that you would never use any sort of soil. You want a bark-based medium. I custom make all my own orchid media, but if you are going to re-pot your orchid, go to one of the big-box stores and just get a small bag of "Phalaenopsis Orchid Mix".
You really can't water from below using orchid mixes. Well you could do so by submerging the pot in a basin of water/weak fertilizer mix up to the pot's rim, but you still need to water/fertilize any aerial roots. I do submerge my pots when they are in the house (when in bloom), but I have to hold the plant/medium down with a hand since the bark will tend to float out of the pot!. Aerial roots would be those that grow above the medium or out the pot's holes. Here are a few pictures of my typical Phal. so you can see what aerial roots are all about. Phal. loves to have their roots growing outside the medium/pots. Notice that the plants are all tilted.
Since I am a seller of orchids, I do my misting/watering/fertilizing way more than the average person. With over 600 orchids, I am always having to water, mist, and/or fertilize something.
I do tell people to always think of the phrase: "Weakly-Weekly" when it comes to fertilizing their tropical plants, orchids included. During the cool/cold months, I dilute my orchid fertilizer by 1/4 and during the warmer months, I dilute it by 1/2. Thus, if the orchid fertilizer label says to use 1 tsp. per gallon, I would use either 1/4 tsp. or 1/2 tsp. Using the recommended 1 tsp. per gallon is fine, you just wouldn't want to fertilize as often and then would want to flush your plant's medium with plain water between every fertilization. That flushes out the salts left in the medium when the fertilizer solution dries.
Be sure your Phal. is tilted so that any water than gets in the crown of the plant can drain out. Leaving water in the crown frequently will cause "crown-rot" and you can lose the plant.
