I use ozone to treat my water after it goes through the RO. ebay DIY Ozone generator kit inside of a small plastic tote, with an air pump sucking from it. Set on a timer to run 3-5 minutes every hour. It bubbles through standing water in a chain of IBC totes. We have iron bacteria so bad that it requires injecting/dumping bleach into the well from time to time...and this setup has been a key to what success I've had in RDWC. Had an entire year of slime issues until I figured it out. This was when locally everybody seemed to be trending out of hydro but between being substantially invested in it and having an (at times) very demanding regular job, I refused to give up on the automation factor.
I'm very interested in how this works out, as running ozone right in the solution was my first idea. Research (reading various forums) led me to believe that it would be ineffective at levels that didn't interfere with the nutes.
I'm also in the process of trying out a venturi setup on one of my systems. I bought a cheap one from China because I wasn't sure how it would work. My RDWC's are setup a bit different than the CC systems. The reservoirs are outside of the rooms all in a row with all of the meters, chilling components etc. all together. There is a (fairly) lengthy run of pipe for both the pressure & gravity lines which I hope to exploit. Municipal systems often use air injection along/in pipelines... it's more effective than the traditional airstone/2ft water column scenario. My pumps are well oversized and are often throttled back so my hope is that the venturi will give me 'free' aeration by siphoning in air, or at least give me a place to inject it. I've experimented with putting small stones down the gravity/return line with good results, except they impede the flow too much.
What kind of DO meters do you guys recommend?