I understand E.C PPM and P.H which im fine with. My question is when setting up a DWC for the first time i will have 4 bubble pots and the main tank. So imagine they are all empty and im filling for the first time. How do i measure out the nutes because if the 4 pots have just water in and im mixing into the tank, when its pumped around surely the mix will be diluted and massively under the amount required do i mix the nutes into every pot and the tank the same then fire it up ? Do i mix 4 x the amount of nutes in the tank and then fire it up and mix the whole thing with the rest of the water?. I know this is probably a stupid question but i just cant get my head around it.
Unless your main tank can hold all the water for all the buckets (12-20 gal ?), the simplest thing is to mix the 4 buckets plus 1 main tank separately. You should do a test on a 1 gallon jug of water by adding a known amount of the nutes you'll be using, then you'll know how to calculate needed nutes in your head in the future. Make sure you know the ppm for the water itself, and then subtract that from total ppm after adding fertilizer. For example, I use the 1 part solid nute Greenleaf Megacrop, and now know that 1 gram added to 1 gal RO water yields a ppm of 125, and a pH of about 6.2. If I wanted 4 gal in each of 4 buckets and 400 ppm, then I'd add 400/125 = 3.2 g fertilizer to the 4 gal water in each bucket. If the main tank can hold all the liquid that will go into 4 buckets, then you can fill it completely with water, and add the calculated amount of nutes. Then open the main tank's valve, and solution will flow to the 4 buckets. Unless you have a re-circulation pump, you are likely to discover that the buckets will have different pH and ppm from each other after a time. If that happens, it might be possible to doctor the main res to compensate. The alternative is to measure and adjust 4 individual buckets.
I thought that would be the case, im using deionised water that is 9ppm so pretty much a blank slate. I am going to be using rockwool to get them going. Should i use canna start in the first mix for the tank or go straight to canna aqua veg as i have both available
I'm still investigating the best nute strategy for sprouts. The standard procedure is to wait for roots to show thru (I use Rapid Rooters instead of paper towel + rockwool), plant into the hydro system, and feed light nutes 100-200 ppm for awhile. My next operation will have me plant seeds in Rapid Rooters planted right in the hydro system with max lights and nutes. But this is something few people do. I'm also a believer that fewer nutes and supplements will yield healthier plants, and never go above 450 ppm (500 scale). In hydro it's safe the use the high humidity that the Vapor Pressure Deficit chart recommends, but that most people fear. Using 450 ppm or less of base nutes only, plus high humidity will produce massive growth and yield without the leaf issues (usually blamed on "deficiency") that over-feeders get.