I am posting this here because my new ISP does not provide access to active hydroponics newsgroups.
I just visited a hydroponics store to buy a large reservoir for my nutrient solution, a Texas controller. They told me to replace the nutrient solution every ten days in order to remove the waste products given off by the plants. I think that that is more labor intensive than necessary. I was thinking that I justreplace the nutrient whenever the conductivity drops below a certain level. I would also replenish used nutrient several times before disposing of it. I do dispose of it by spreading it on plants growing in the soil.
My question to the group is: What waste products do plants produce that leave by means of the roots?
Bill