Damn it start to be pretty neat over there ^^
On your water rates, it look like turned in one direction : dirty delivering “plumbery”. A flush can be salvatory i guess (even for the humans living there ^^). Just to give an idea.
Neutral + PH, hard water, carbonated, high QAC (enemy of CEC) … it look like you have dirty delivery plumbing. So the water wait inside dirt before being delivered to the house and carry some funks.
It’s possible to operate a flush of the house and from the house, but depend mostly on how it’s build, no generic solution.
I mostly used it for motherplants but Ebb&Flow and coco is the most efficient combo for the level of retention and it’s fastness. By laziness i often used GHE tables (1sqm ones) but they have their flaw : the tank volume necessary that i find quite stupid, specially in plain summer.
If you can limit the volume of water that need to stay in the pot’s table for a cycle, it will be better overall. And the tech being quite simple, it’s possible to build it in various way. There is one quite compact overall here :
Now you have to think about the medium and to dodge the usual traps, IT HAVE to possess a good water retention for good cycles and perfs. Rockwool is good on this point by example but give far better results with very oxygenated setup and letting the roots live their life : 15% NFT, DWC, Aero, drippers … PH is also quite low and your water isn’t specially playfull for this atm.