Aergoarden Grower - First Time!

I have set up my aerogarden and put in some nice seeds from here and there collected from smoking good weeds.

I have had my plants in the aerogarden for only a few days and they are all sprouted and growing very fast.

So far I have only used one nutrient tab (small) and they seem to be doing pretty good.

Two of the plants have purple stems, and one is green. Is this just the strain of the weed? Or should I put in one more tab of nutrients (small)


Here are some pics below

na man no tabs or nuts until ad least 2 weeks. the seeds have enough nutes until about 2 weeks then add 2 tabs every 2 weeks or 1 tab every week

well... will they still be fine with that water or should I go empty it out and put clean water in