Hydroponics Forums Discussions - the time between changing solution

How much time can be added to the time between changing solution by using pH and nute dosing systems? How would one go about having the change happen automatically? I don't mean that some robot walking around measuring out cups of gh gro and bloom, but what about bleeding? One time I tried making a large reservoir for my Sunshine #4 soiless garden by using various chems to attach chunks of garden hose between the bottoms of 35 gal trash cans, but none worked. Then I tried siphons, but it was hard to see if they were working as I had to wait for a few waterings to see if the levels were changing. I want to try hydro because even though there is some more room for play with soilless, there is not much, and I found I was tinkering all the time anyway. I want a garden as automatic as possible. I have 5 yrs experience with 2400 watts of hps for flowering and understand that there is NO way to avoid manual care and attention, but still I want to invest over a grand for the dosing. I want to use clay pellets with flood and drain setup I'll custom build. Obviously, the larger the res you use, the less often you have to replace, especially with dosing, but would it be practical to create a res that's large enough to last a cycle (3 months)? How do I go about having different ratios of gro and bloom and mico with the dosers? They all seem to dump equal parts of a and b. Maybe dilute one of them? Also flood and drain seems to suck with auto topping of the res with water. I could submerge the float down in the res, but I just don't trust the seals. I'm a physics/engineer and know that all shit fails. Thanks for the time.... My advice to all: RO water is awesome. Great for drinking to - and for house plants and fish tanks. Salud Lizzy