The down spout is a great way to FLUSH the 'internal reservoir'....I have very small holes with rubber stoppers at the bottom side of each bucket....As a sanity check, and at any time, I can pull a rubber stopper to check how the internal rez's are behaving.....It VERY possible for pH to drift up, AND even more so, the TDS....if there is any type of deviation, its easy to dump a pH, AND TDS balanced solution down that spout and let it come out your drains.....It's better than dumping a BUNCH down over your root ball...PLUS, if its a pH fluctuation, you could dump a 5.0 mix on top of a rez that is at in the mid 6's to BALANCE IT...then check....Once your #'s are 'CLOSE', regular watering with pH and TDS correct solution will keeps thing stable (for a while), sanity checks once a week keeps it correct....
Feeding should be EVERY WATERING...I.ALWAYS water till I get about a third RUN-OFF.....I.rather do that and 'waste' a little nutes, than have fluctuations that would cause issues....I use 3 gal buckets...I've used 5 and found there is no difference with plants the size I grow....I water every 3 days, with good runoff, and it Rocks....When I transplant into the main room (from nursery), they are on ALMOST full strength grow nutes....Once under a halide, they really take off....Within a week, go to full grow nutes...They get full GROW nutes until a week into flower....GROW nutes are needed to support that heavy stretch, the 1st week of flower, even though the timer is 12/12....MOMENTUM going into flower greatly dictates how well they are going to do....Break that momentum, and they won't reach their full potential...that can easily happen, if they were swapped right over to flower nutes with the timer flip...Slower growth, premature yellowing (or worse def) can all happen during HARD STRETCH the lacks nitrogen.......THEN, I swap to Full Bloom formula, until its time to reduce it, in preparation for flushing......
also keep im mind, when I transplant INTO the main room, these are plants from cuttings I took off the last crop, they day after I put it into flower...Gives me time to root and get them prunned a cpl times and VERY READY to start growing...No MOTHER plants needed that way too...They have made adjustments to higher grow formula by then too...I usually up it a week prior to transplant too, to get them growing fast (under quality T5 lights)....Then all I need to do is increase the grow formula ONCE about a week-10day after transplant, Then swap to full bloom, 7 days into flower....EASY RECIPE to remember.....I am using 1000w HID lights...Someone using something like 400w lights, would need to be using LOWER TDS #'s.....Each grower needs to tweek recipes to WHAT THEY ARE DOING....YT