Use a mesh filter bag on your pumps in rdwc. If you start to see shit building up on it, wipe that off, and change the water. Otherwise I just top off. I've only changed my girls water one time this whole grow.
Topping off with mixed water right? I have heard of people monitoring PPM as a way of determining when to change water but I would guess that would only work if you are topping off with straight water. Do these plants have a nutrient intake that doesnt involve drinking the water they are in? Can they absorb what is in the water without absorbing the water?
Well... i love this question... it made me go "Hmm.."
See cuz the plant is gonna drink the water, it simply must, right...
BUT...
Would one ask "Can the plant uptake nutrients from the soil without actually consuming the soil?" Sounds simply silly doesn't it? So perhaps yes, it CAN uptake nutes w/o consuming the water... technically? Or consuming very little.....
I dunno, seems like something to explore, but bottom line, if ur room temps are nice n low, it will drink less water, regardless of nute needs.... ..... ......right?
Ding ding ding .Pretty sure the plant takes the water out of the soil right? and any nutes in the soil would be absorbed into the water and then into the plant? (I dont do soil at all right now)
I would imagine the nute companies would all agree to recommend 100% water change every week, my question is why 100%?
Most of my experience as far as maintaining water parameters is coming from experience reef keeping (Nano reefs). Water changes take care of a lot of issues like removing nitrates, etc.. but with a water change it also will replenish calcium (used for coral growth target around ~420ppm) which will drop over time as it is used up by the coral (usually ~380 when i do water changes) but by removing 20% of the water and putting newly fresh mixed water (adds calcium back in) it will replenish the nutrients that were absorbed by the corals. at least thats my basic understanding of it... so why would this method not be used in a rdwc?I used to change every week but this run its stayed so clear. I just keep on a addin.
so why would this method not be used in a rdwc?