@rDWCNoob so in theory if my rockwool ec itself is too high I can just keep feeding causing runoff till desired ec? Won’t post pics till they’re healthy lookin lol sitting at 2.0 right now even though I caused some runoff with .5 ec it’s steady 2.0 assuming some nutes from original soak are still hangin in
generally speaking yes, you should be able to flush till the runoff is the same as the res. I wouldnt go too crazy though. I dont actually check my runoff ec, jusy my res. And I usually go off of PPM instead of ec. In veg I keep the res at 600-800ppm then 1000-1300ppm in flower. With how often you water, especially in veg, your root zone ec should be fairly stable because the rockwool is completely inert, it doesnt hold nutes at all.
In my experience flower is where things can get a little spicy in the root zone because youre allowing more dryback. If parts of the block get too dry you can get salt buildup in the cube, which i think is where you can see your ec spike with rockwool, but i dont have sensors and dont monitor it that way. What i do is look for tip burn and then increase my feed time/runoff to try to flush the cube a bit and maybe water down my nutes a bit, but not too much. You dont want to increase or decrease ec too drastically all at once as that will change the osmotic(?) pressure around the root cells and cause them to take up water too fast and burst. If you need to flush the block, do it with whatever feed strength you normally feed with and maybe water it down a bit. Dont flush the cube with just water mid cycle.
Again, its a completely inert medium so the plant generally gets exactly whats in your nutrient solution on every single feeding, which is one of the reasons its so great for crop steering. You can make even small changes to your feed and the plant will benefit from those changes very quickly. The caveat is that it will also react quickly to bad changes to your feed/res, although not to the same extreme as say rDWC. You wont see the same kind of swings unless perhaps youve got a recirculating res.
You can also flush the entire block at any time with just an extra long feeding, veg or flower, till you get the desired runoff. Just dont do it with anything too far off what youve been feeding, you want replace whats in the cube with whats in your res, which in theory, should be exactly the ec, ph and temp the plant needs.
Mostly you really shouldnt need to flush it at all unless theres a problem, ie. it dried out too much due to say a pump problem, which happened to me on my last run lol. However, its not necessarily a bad thing either. The 4 plants that got dried out the worst, looked the worst, had the most nutrient burn and also unfortunately were the smallest plants, had the absolute best smell and flavor by a long shot, although they were from a different mum as well, same strain. Ill find out on my current run, which is clones from all the same mum, if the added stress at the end really did increase the terps and flavor, which in theory it can and does.
With your sensors you should be able to dial the wc in and avoid most of that nonsense lol. You should just be able to keep your res within your desired levels and let it do its thing. So long as your nutrient solution is on point, and your pumps and sensors are all functioning, youre all set.