Help with Phal Orchids

I am new to houseplants although have outdoor gardening experience. First house so getting the hang of all this! I have a mini Phal orchid from Whole Foods which is in a window my mom suggested I put it in. I am in NY state if that helps. It is a SW facing window and the orchid is on the sill. The leaves are turning yellow toward the bottom but new flower buds are forming. Is the yellow a problem?

I also got a clearance large Phal orchid from Lowe's. I know, I know - addiction beginning! Anyway, I bought it because the flower stalk was dead BUT the leaves were strong and dark green and the roots were green and perfect. I cut the dead stalk off at the third flower nodule and got a crazy idea that it had to be nurtured by repotting in a bark/perlite/charcoal Orchid mix I bought. I used the same pot - just replaced the styrofoam and moss that was clumped in and stuck to the roots pretty bad with the Orchid mix. Now I'm freaking out because there were so many roots that to get the potting mix in the same pot - plastic in ceramic - I had to struggle. I also added some spagnum moss. I'd say it's 75% roots in there and 20% mix and 5% moss. I also put a few small rocks in the ceramic pot so its up a bit. I don't think it's holding moisture so I've watered it twice in a week - once with weak Orchid fertilizer. Is this lack of potting mix a problem? I have this orchid in a NE facing window that I don't think gets much light during the day as the neighbor's house is close by on that side.

I want to keep both orchids away from my pets and so I'm a little limited on where I can move them to. I'm afraid I fussed too much with the rescue Orchid from Lowe's and shocked it - although its only a few days ago I bought it so I don't see any change in the leaves yet. I would appreciate any advice. I'm new to this and think I might have done more harm than good.

Meghan

Bottom leaves yellowing is normal. Water when the roots are gray colored. The roots turn green when wet. I use CLEAR pots for phals so I can see if it needs watering. I used to kill a lot of phals over the years until I used clear pots. Keep it OUT of direct Sun. Bright, indirect Sun is best.

Okay, so I freaked out a little and saw too much black on the base of some of the roots of bothplants so I mixed Physan 20 according to instructions (well maybe a little more than that!) and sprayed down the bottoms/roots of the orchids. Time will tell.