I have six girls that are three weeks old from seed. Just transplanted from solo cups to one gallon fabric pots. Soil is FFHF. I gave them a watering once this week. One gallon RO with 3ml Calmag. I used the one gallon of water for all six plants. No run off to check. Light is E420 at 18" off top of canopy at 50°. Temps are consistent around 70° and 60 RH. Never given any nutrients. I use a probe to check soil moisture. I wait until it's dry before watering. Should I do a good watering and check PH and PPM's?