FYI Im not planning on starting the O2G only grow here, but could change my mind is enough people let me know they are interestd
I'd be interested to see how it goes if you send me a message. I think you'll definitely want some kind of agitation in the water around the roots.
Just FYI these emitters break down in especially in higher salinity solutions and leech metals into the water. They also do not really super saturate the water with do like they claim. They do however increase the dwell time of bubbles so much so that a DO meter will pick them up as DO.
I would imagine they're probably stainless steel and so, as you mention, will gradually pickle. This also happens with platinum (if you put platinum in saline at a pH of about 1 and add an oxidisers, such as persulphate or peroxide, it'll start dissolving into solution - they use that trick to recycle catalytic converters without autoclaves or aqua regia). Whether or not it's a problem is another thing I guess. I suspect you may be able to saturate the water with oxygen using relatively short bursts. Could always use magnesium for the electodes
I've tried growing, temporarily, using H2O2 in solution, solely (no air pump). Peroxide has a relatively long persistence in water apparently, even at low concentrations; check this >
link< where they measure the degradation. My hope was it'd help kill off any germs and also provide oxygen to the roots; it definitely does break down into free O2 when it contacts the roots as you can actually see it fizzing if you use higher concentrations. I didn't run this for long enough to know whether or not it'd work over a full grow. It did seem to keep the nutrient reasonably clean; I was running it in a clear container (exposed to light) but didn't have any algae growth in it initially.
Something I did notice, using
Advanced Nutrients hard water veg, was that after adding just a few mL of peroxide every few days to 4-8L of water at ~1000ppm nutrient, I could see what appeared to be something flocking out of solution (opaque white fluff). At first I wondered if that might be the hard water additive chelating (ligand binding) minerals out of the water. But I already had some mixed up that had been sat in a bottle for weeks / months that was still perfectly transparent.
I strongly suspect what was happening was that the peroxide was actually oxidising something within the nutrient itself. Peroxide is a none specific oxidiser, so it'll oxidise anything around that can be oxidised; including organic material in the nutrient. The nutrient solution itself didn't appear to change at all in terms of ppm reading, but that could easily be because the things it's oxidising in solution aren't conductive to begin with (the ppm reading is essentially a conductivity reading right). The peroxide oxidises whatever it encounters first that it can most readily react with. One solution to that may be to add something to the tank to preferentially cause it's decomposition.
I've read many blog posts (re-posts of re-posts?) claiming H2O2 is really simple to use but I suspect I've observed something others haven't due to it being used in a transparent container to begin with (so I could actually see what was happening in the nutrient tank - the flock forming). I would be curious to know if something similar happens using the electrolysis idea, as oxygen radicals will temporarily form near the electrodes, which may then also react with the nutrient itself.
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