Howdy all! This my very first post in here or anywhere. I have been following the basics and using all the trouble shooting advice offered by the many afficianados in here. My question being a newbie to DWC system is the ideal ppm in my res. at the dif stages of growth. Also, fighting to keep dowwn the ph in the res. Does light effect the ph? Trying to figure out why everyday I have to adjust the ph that rises to 7.1. Any advice would be helpful.