Many questions about hydroponics!

[Davephan]

I've been watching a lot of YouTube videos about hydroponics and I would like to get started! From my understanding using hydroponics is far more efficient than using soil. I live in Minnesota, where the growing season is very short. Hydroponics sounds like the ideal solution to enable me to garden all year round. I have many questions which I haven't found answers yet.

Can the grow lights be run 24 x 7 to increase production, or do plants need to rest from the light? Are there diminishing returns running the lighting 24 hours a day verses about 12 to 16 hours a day?

If the lighting is run 24 x 7, should the watering in a non-static system also be cycled 24 x 7?

Roots need to be in the dark. I assume in as close to total darkness as possible. The hydroponic growing channels seem to always be constructed with white colored plastic. If black plastic was used, inside the channel would probably be darker. However, outside the channel, the black color would absorb more light instead of reflecting light in the growing area. Does the white colored plastic provide a dark enough environment for the roots, while allowing more reflecting light in the growing area?

led grow lights might be the best lighting solution, since the heat problems are eliminated and the energy consumption is drastically reduced. Is the main negative against LED the higher cost, compared to using HID or hps lighting? There are many types of LED lighting. Some systems are priced below $100 and others are $1,000 and more. Are the less expensive LED lighting a good compromise instead of purchasing the expensive LED lighting? Is there a point of diminishing returns that is beyond the less expensive LED lighting?

In Minnesota, the growing season is quite short. The tomatoes and pepper crops I grow outside seem to be at their peak of production, when they are all killed by the eventual frost that always comes after a short summer season. When growing plants inside in a controlled environment, can plants produce crops continuously for years, do they go through cycles, or do they taper off production over time?

What is the ideal liquid temperature range?

How important is accurately measuring PH? Is a cheap $20 tester good enough, or is it important to spend closer to $200 for a better quality PH tester? I am using city water that I plan to let sit in containers for a day or two before the water is added to the nutrient tank. I plan to use the MHPGardener Masterblend hydroponic nutrient mix.

Which of the 4 methods, Ebb & Flow, Drip Method, Nutrient Film Technique, or Passive System produces the best results and which produces the worst results? Is there a large productivity difference between the four methods?