Unless you used something to scoop water out of your water bucket that u dipped into one of your teas or anything organic prior to using it to get water out of your water bucket and then "double dipped" it back into the water, that should be the only way you'd have something growing in there, but I don't know how it could keep living on just water without a food source to thrive off of... Aside from that, I'd say the only thing you'd have in the bucket itself could be algae if light was getting in... it is wise to clean the water barrel/bucket every so often with h202 or something... when using municipal tap water the chlorine kills off anything as you refill it... it's not to say shit can't happen but it's less likely... you can use a combination of tap and Ro... use enough tap to keep your ppm around 100... again that's with city, and as mentioned, all water is different.. some city water isn't good to grow with... take the flint issue for instance but most municipal water can be used but it's always a factor that needs to be accounted for/adjusted to....
Also if you have the discharge hose of the RO maker somewhere that microlife could get to it; it could back track into the RO system/membrane... that or if you have well water that has issues already... those are the only ways I could see...
You should use something that only gets used to get water out of your main water storage bucket and doesn't get put into anything else where you can transfer whatever back into your water bucket and pass it along to everything u use the water on...
Also as mentioned above, with hydro you need to keep water/tea/nutrients/whatever's temps in check (below 70, 65-68 ideally) as above that the oxygen levels are low and create the perfect environment for root disease/bad bacteria to thrive...
But if you always got root rot you were obviously doing something wrong, (no offense intended)... honestly this is why I run 100% synthetic nutrient line and h202 to create a sterile reservoir...
way back when.... I got the bright idea to grow some weed; with nothing but an idea, a high times magazine and internet access... I was obsessed with yield....cuz I was gonna grow like 30 #'s a week with $200 worth of cfl's and a couple T8 flouros, all in my spare bathroom, lol... so naturally if yield and fast grow times were what your after, hydro was my obvious choice... I diy'ed a couple dwc buckets and managed to grow a whole lot of nothing... all I did was end up struggling and destroying the one thing I spent $ properly on (genetics)... so I switched to dirt and found my way... but with some patience, experience and out of necessity, I recently switched back to hydro...
Water temp control is absolutely imperative in 95% of hydroponic growing, the other 5% being passive/drain to waste hydro where water/nutrients are not reused... but if you have roots sitting in water for any length of time, u need to keep water temps right/oxygenated as mentioned... if you don't know the basics of organics... I'd suggest going with the sterile/synthetic nutrient route as I have... and I know organics and teas and all that good shit from when I grew in soil.... but organic hydro is an experienced growers game.. and you need the right system to grow organic hydro, I'd say UC systems are probably the best for it based on my limited knowledge due to the fact the water is constantly circulating and never gets a chance to get stagnant but a chiller is a must due to air/water pumps and all other heat creating factors....
if your dependent on the coming crop, it's not a wise move to jump onto the organic wagon without knowing the basics... in soil you have a lot of room for fuck ups growing organically but organic hydro and hydro in general is unforgiving if you aren't 100% on point and on top of shit... things happen in hours where as in soil it takes days...
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