After comparing notes with a friend whom also grows hydroponically, here are some things we agree on regarding saving water and nutrients:
Less is more when it comes to nutrients. We have both found that we achieve good results even if the nutrient level stays below 1,000 ppm. In fact, I've had good results below 900 ppm. That's keeping it below 500 ppm during veg cycle (350 to 500) with a ramp up to the peak about 2 to 3 weeks before harvest and then a tapering with pure water to bring the ppm down before harvest.
Going easy on the nutes means you shouldn't have to dump your reservoir and clear rinse every few weeks. That is a huge waste of water. When I do empty my reservoir by the way, I dump it on the blackberry bushes.
In the photos below, the plants are in a 3'x3' flood table with a 30 gallon reservoir. Water usage would look something like this:
24 gallons to fill the reservoir to start and about 10 gallons added through the veg cycle. After that it will average 1.5 gallons per day for about 60 days. That's a total of 124 gallons. This set up usually yields between 12 and 14 ounces. If we take the average yield of 13 ounces we get a figure of 9.5 gallons of water to produce 1 ounce.
The strain is Green Candy by the way.
Please upvote and follow.
Thank You!