Phragmipedium Nicolle Tower purplish blotching help

[JennyNE]

Hi Everyone! My name is Jen and this is my first time posting here. Hopefully I choose the right thread and do this correctly. Lol. I live in Maine and grow Phals and Phrags. The Phrags I just starting growing Oct 2019. So they are still very new to me. Also this is my first winter using a grow light. I have a full spectrum Sunblaster T5 4ft light. They have been under the light for about 1 month now. Anyhow the one I’m having an issue with is the Nicolle Tower ( d’alessandroi X longifolium. It is now has its first flower and a second on the way. But I’m nervous about the base of the plant. It has purplish blotching. The leaves are light green, but at the bottom right where it meets the medium the purpling seems to be spreading upwards to under the leaves. Under the first leaf I noticed a small split starting and also the purple coloring. Also when I got the plant it was in rock wool which I am not used to so i reporting into medium orchiata bark, small charcoal, sponge rock, and small pieces of spagnum moss. There is a top dressing of spagnum. We have a wood stove in the house so I try to keep moisture around the top. Put temps are 73 to 74 daytime and 64 to 67 nighttime. Humidity around 35 to 45%. I feed distilled water mixed with 1/4 1/4 well water. Come out as 10ppm with ph of around 6. Also I feed 2 times weekly around 150ppm (MSU fert + calmag) and monthly with Kelpmax. Sorry for the LONG post but I thought as much info as possible would help. Long story short anyone have ideas of why the purpling is happening??