[GpsFrontier]

The first night I moved some of my plants into the larger system, I didn't have a timer on the pumps yet and I simply turned them off for the entire dark period. The next morning when I checked on the plants one of my pepper plants had drooped all the way over and was laying on the lid of the system. About 15 minutes after having the pumps on again the plant was perked back up and standing tall again....so it obviously didn't like not getting any water at all (even though it was in a net cup filled with hydroton and no real root mass extending out of the pot yet). Yesterday I was able to get the pumps back on a timer running the 15/15 cycle during the light period and on a 15 minute cycle every 2 hours during the dark cycle. Checking on the plants this morning they all seemed alright and (at least somewhat) happy. I think I'll stick with this cycle for a while and see how things go.

Plants that small tend to respond much faster to there environment. So even though they don't feed during the dark, it's wise to keep an eye on them and if you see wilting to increase the watering frequency. With my pepper plants, they got watered 30 on 30 off all day, and until about 1 hr after dark, then started 30 min before first light. During the night I watered them 3 times at 30 min ea with no wilting at night. This was during summer when the night time temps were around 95-100, and day time temps were got up to 115 at that time. I started with store bought plants though, so they were already about 6-8 inches tall and the relative tempuature was a little cooler. I also had them in upside down 2 litter bottles with a mix of grow rocks and coco chips. Coco chips hold moisture better than grow rocks.

(NOTE: You want the watering to continue into the dark (not twilit), and you want it to start at least 30 min before twilit.)

Right now I have 3 systems running. One gets watered twice during the night for 30 min each with no wilting. The other two are on the same timer and only get watered once at night from 11:30 pm to 1:00 am with no wilting. One of these systems is using 3 inch baskets with coco chips and the other one is 5 gallon buckets, also with coco chips as the growing medium. The temp is getting into the upper 40's at night right now, so heat is not an issue. I can probably cut back the watering for all 3 systems at night, but it's not hurting that I can see. With growing plants there are so many variables, the growing conditions, type of system, all the variables of plants growing environment, that observation is your best indicator.

Some of the plants (tomato especially) just don't seem to be as healthy as they could be, so I know I'm not "on the money" just yet.

I am learning how fickle tomato plants can be myself. Mine seem to have a virus or something that is stunting their growth as well as curling the leaves. Through some back and forth with the guys at General Hydroponics, as well as some extreme close up pictures I took of some insects that were later identified to be "Winged potato or pea Aphid's," we are narrowing it down. There are also other factors that are probably contributing, like nutrient temp, the variety of tomato plant itself, as well as cold weather. But it might be just easier to start over because they are still small enough to do that. Trial and error, process of elimination, and observation is the key to learning.

General consensus seems to be that plants early in the life cycle need lower ppm. Additionally the consensus seems to be that in a recirculating system ppm can be lower too due to the continuous feed of water/nutrient.

Yes, small plants wont need a full strength nutrient solution. Seedlings probably around 25%, 3-6 inches probably around 50%. But again everything is not exact because of all the variables, and trial and error and observation are the keys to learning. If you had two growing chambers you can do some testing and see what gives you the best results.

Think I should go that low? Or maybe just drop it by half and try out a solution of about 500-600ppm?

PPM is simply a measurement of nutrient strength, unfortunately a PPM meter can't tell you what elements are in the nutrients and their individual concentrations, just their total amount. For this reason I haven't even gotten a PPM meter. It will however tell you how fast the plant is taking up the nutrients that it is taking up. If you know the type of plants you are growing use more nitrogen this could be helpful, but as I can see only if you can just add back the nitrogen. With pre manufactured nutrients this is not an option.

Just adding more nutrients to the solution to bring it back up to the the desired PPM wont insure the nutrients are in the proper proportions. This is because plants will take up the nutrients they need and leave the rest. One plant might use up more nitrogen, then by adding more nutrients to the solution you would be adding all the elements to it, so the elements that the plant did not take up would be in a higher concentrations, and not in the proper proportions. Most beginners find it easier to just change the nutrient solution regularly, and then get over that initial learning curve first before trying to tackle nutrient composition.