As you seem to be asking for general overview info, I would cite hydroponics lessons presented at a couple URLs, and the FAQ for this forum. Both links have a separate commercial side (online store), but the sequential lessons don't seem to have embedded ads. Hope this is a start, and best of wishes in your instructional endeavors. -v

Hydroponics Online Lessons

Hydroponics University

What info are you looking for?

I've only germinated seeds twice, but you can see the results after 11 days at the link below. They're mostly tomato seeds, but parsley and basil are also coming up nicely.

How'd you do it? How much time do you have?

Here is a link that might be useful: Seedlings

I constructed a very simple to build and low cost hydroponic drip system for tomatos. I bought 2 18 gallon totes at Walmart, and then bought a 130 gallon per hour submersible pump. I have flexible plastic tubing, half inch, that runs to an adapter screwed in to a 24 inch dual threaded PVC pipe. I fill one tote with about 9 gallons of water and add nutrients (I use Flora Grow, Micro and Bloom). Put the pump in the water/nutrients, and run the PVC up through the top of the tote. Punch several holes in the top of your bottom tote. Then take your other tote, punch several holes in the bottom of that, and a hole to punch your PVC pipe through. Take the top of your top tote and cut holes in it to hold plastic planters (I use 3 inch circular with a vented bottom). Run the PVC up through the top tote and through the cover to the first tote. Get a six outlet irrigation sprayer that will screw into the PVC. Get tubing to run out from the six spigots. Put your plants in the planters, surrounded by either rockwool, or expanded clay pellets and run the tubing into the planters.

Then, get a cheap aquarium pump and an airstone and place that in the bottom tote water/nutrient mixture. (The airstone adds oxygen to the nutrients and makes it easier for the roots to drink it). Turn on the pump and you will have a drip system. The good thing is that there is plenty of room in the first tote for all the roots to dangle without soaking in nutrient, and all the liquid drips back to the resevior, being further exposed to oxygen on the way down.

Every couple of days, add back the water that was absorbed or evaporated, and every week to 10 days, change out the nutrient solution. Using the Flora 3 part system, it will tell you how much of each nutrient to put in the water each week. Typically you put heavy emphasis on grow until about 6 weeks, then it shifts over to the bloom fomula.

Its a very low tech, very easy drip system that takes up a small space and is low cost. Works well for all kinds of plants, not just tomatoes. (I have a watermelon that is growing like crazy in it!)

Basically the information we're with out right now is how far the lights should be above the plants and when they should be introduced within the growing period...

(we have a 250W MH lamp growing about 8 plants)
(we also have a 400W MH lamp that we are not using at the moment)

any help would be much apreciated!

I grow with HID (MH and HPS) lights and you will need 20-50 watts/square foot of plant canopy.

HID lights should be 12-24" above plants because the lamps will burn the leaves if they are closer.

You can start with the lights on as seeds are germinating, but lights are not required until you have plants with the second set of leaves.

You should also get a light with more red in it than MH as your plant flowers and fruits.