So i am going to be running a 4 bucket RDWC. I will have a 18g reservoir where i keep my mixed water with nutrients. I was wondering to make it easier and healthier on the plants to keep another 18g reservoir full of just ph'd water. This second res would sit ontop of a table and have a auto-top off connected to the mix nut res. I drew up a pic (high drawing lol). Would such a thing be worth doing? I figured it would keep the Ph of the water in check as if the plants were eating more water and the nutrrients would stay the same.
It would work just fine. The only benefit form it would be if you are unable to check on your system everyday. If you go two or three day with out checking during flowering you my need the extra water. However if you check it every day it is not needed. I run a 36 bucket ebb n grow system with a 55 gal. res.. The res. is big enough to supply the system but I added a second res. just in case I am unable to check on it every day. The one difference between my system and yours is that I may have enough water to keep my plants alive but not fill the buckets and then my fill pump would run dry and burn up, you don't have to worry about that.
Yeah basically that is the reason why i wanted such a back up feature. I might have to leave the plants un attended for 2 days a week.
i don't think your plants will drink all that water in two days but its always better to be safe then sorry