Questions Regarding Reservoir and Nutrients

This may seem like a stupid question, but here goes any way.

I have a recirculating system which totals about 10 gallons. This is the control bucket, and the grow bucket. Then I have a 20 gallon reservoir that gravity feeds the control bucket with a float valve.

My question is: Do I mix the nutrients in the reservoir, or do I just have pure water in the reservoir and mix the nutrients as needed in the control bucket?

Either would work but I suggest the reservoir. If u mix in the control bucket and it needs to be topped off by a plain water reservoir then your nutrient levels will be diluted. Mixing in your reservoir will keep your nutrient level the same all the way through. Much easier to maintain.

Thanks