basic hybrid phalaenopsis care
1-light : low to medium and never direct sun
2-temperature : intermediate/warm
3-watering : on a week as you do seems to be ok. You can remember that roots should never stand in water
4-feeding : use fertilizer
For spots, very difficult to say without photo. Check system root of the plant
Purple spotting can be to much sun, virus, etc..... Some phals have purple leaves...