Well, I learned something yesterday...
At this stage, when I can no longer take the plants out to rinse the roots, I must NOT rinse them in the tub.
Little pieces of roots were knocked off in the process (lots).
I was aware and checked the screen over the drain every hour after refilling and replenishing the system, for a couple hours, and there was a bunch.
Then we went off for a while and were gone a little longer than I wanted.
Anyhow..... DISASTER... (easy... plants are AOK)
The drain screen clogged and the root tub overflowed.
And, of course, the res keeps on pumping more and more fresh water up there courtesy of the auto water valve.
We were gone about 5 hours.
Shed floor was flooded and when I opened the freezer door, water rushed out.
So, I drained everything and started all over, not disturbing the roots as much as possible.
Again I checked the screen every hour till bed and the amount was less and less, so I felt safe going to sleep.
At 6AM lights on, everything was OK.
BUT, I did however turn off the fresh water add back last nite... just in case.
ONE of the tweaks in the down time between grows will be SOME kind of a safety cutoff system that will stop the pump in case of an overflow.
AND a drain from the freezer area down thru the shed floor.
That would be great, but the bottom line... from here on out... I simply drain the root tub, clean the lower res and refill.......
One positive thing is the roots got a thorough flushing and I'm certain, to some degree, the plants got a little flush as well... and the grass around the shed is gonna grow like a mofo !
Sheesh !