I am liking the Hydro thing but I need to really learn about mixing my nutes with PPM and pH. Not as forgiving as soil. I am wondering how big the plant will get in that coffee container? Its getting bigger every day. Do I need to just ad water to the res when its low? Does the water need to be pH to 5.8 or just plain tap water?
She'll get as big as you let her or until the root mass literally becomes physically too great for the volume (check my journal for some pictures of a plant I have that is at that point). Becoming root bound won't ever really happen since the roots are going to be in contact with nutrients as long as they are in the bucket. If you are going to let her get big, you'll want to get her a bigger bucket eventually. As a personal guideline, if I have to top-off the bucket more than once during the week: it's time for a bigger bucket or a severe pruning back.
Don't overcomplicate nutrient strength and EC/ppm's... you are still feeding the plant the same way as in soil. So you'll want to start nutrients at a light/moderate amount according to the bottle label (just take your EC readings for future reference) and over time, experiment with pushing things higher while reading the plant. Further down the road, you can forget about the bottle label and reference those previous (and exact) EC/ppm readings you took
and then continue to fine-tune max strength according to EC/ppm's.
As far as pH goes, you'll probably notice that if you mix up a new full-strength batch of nutrients that the pH should be right around a 6 - and want to stay there due to the buffers in the FF nutrients. If you are getting between 5.8 and 6.2 pH after mixing up a new batch of nutrients - don't split-hairs and try to chase the pH around by tenths or hundredths of a point using a pH adjuster.... you'll just make things more difficult for the plant. About the only time I have to use any real amount of pH adjuster is when young plants/cuttings are being given less than half-strength nutrients (due to the buffering also being weak). Take a pH reading every few days or so just to make sure there's nothing wacky going on - but otherwise it really shouldn't be fluctuating that much over 7 days when it will be time for a new batch of solution. Any water/solution that goes into the reservoir needs to be pH adjusted prior to being added (even tap water for example).
As far as when the water-level starts to drop as the plant drinks/feeds, relax a little here as well... all you have to do is make sure there's at least enough solution to keep the roots wet and the air stone bubbling. There's a lot of lee-way here as far as the water level goes. I usually wait until they are about half emptied, then I top them off back to full with plain/pH'ed water. Sometimes I top-off frequently and sometimes I even let the buckets get mostly emptied (not recommended though)... But the general rule is after you have topped-off with an equal amount of water used to mix up the original nutrient solution: it's time to mix up a new batch of nutrients even if a week has not passed. That's it, nothing complicated.
Further down the road once you have your desired base-line EC/ppm readings established, you can "add-back" nutrient solution to maintain that EC/ppm level instead of "topping-off" with plain water and changing the solution weekly. But in my personal experience, this is not really any better or worse as far as the plant is concerned, and is a little more work with more room for error. I stick with topping-off plus weekly reservoir changes (aka "drain to waste").
What a nice St. Patrick Day picture.
