not true man.. i use only HPS ballasts... i will never use a MH ballast.. your plants will grow fine under an HPS with full orange or red spectrum... but id you have a full HPS only ballast go to your local hydro store and get a HILUX GRO bulb.. its a bulb for an HPS ballast with 100% blue spectrum.. so there is no need for a MH ballast...... but like i said you plants will grow just fine during vegg even will a regluar HPS blub.......and as for purple strems is stressNo hps is no better then 2700s. Hps are used for the most part flower only. Looking closer at your pic your stems are a little red too. I can't remember if thats a nute dif. or a ph problem.
more lights really? i think my hps will do just fine i only got 4 plants i think tomorrow ill throw up the hps and keep it a foot or two away i feel comfortable and thx for the adivce W i did read purple stems meant stress but that cud be just from it being a lil to cold at timesya get more lights
like new smokey said, do the hand test thats prolly the best way if your not sure... during veg with my 400HPS i like to keep em about 19inchs - 24inchs at the most,how far from my 150 watt hps shud i have my seedlings? i put them about 8inches away and it got a lil to hot to fast so i dropped them down to a foot away and i noticed some lil black ball shapped stuff on the tops of my rockwool maybe mold?