This thread is meant to be informative but not suggestive. DO NOT BLINDLY FOLLOW THIS ADVICE, BUT PLEASE DO COMMENT!
Hydroguard is expensive, and as I’ve found has a shelf life (6 months from opening bottle) as well as an expiry (can’t sit on shelf for 2 years) – so getting a good bottle is key, and not always possible depending on location and what stores import it or sell it. It also has strict requirements on storage, let it get too warm and I believe it is not as effective as it should be any longer.
From my research, there appear to be two main camps of hydroponic growers:
- Those that maintain a “sterile” reservoir, or one without beneficial bacteria or any bacteria at all for that matter.
- Those that maintain a “living” reservoir, or one that contains beneficial bacteria which should (in theory) keep the bad stuff in check given the proper conditions and treatment.
Most of the recommendations on this forum, if not all of them, lean toward #2. Both of these styles have their pros/cons, and their own sets of parameters and norms. I have found that the existing environment (or ability to change that environment as needed) is the single-biggest factor as to whether or not the grow will be successful when applied, i.e. in either case it boils down to “what works for you” and “how much you’re willing to change it to get it to work”.
In my case, I can’t change the air quality in my condo without doing extensive renovations or purchasing expensive air purifying devices, and I rent, so finding something that works without “dealing with the dust first” was paramount to me. Additionally, it gets hot and humid here in the summer, and my A/C unit is literally glued into the wall (contributing to the dust coming in, can’t replace it with better unit + hepa filter), I can’t change the filter, so that leads to me doing things like vacuuming it out and spraying it with compressed air cans to get it to blow cold again and that only deals with part of the issue it poses.
I’m a noob in growing hydro (started 6 months ago) but do consider myself to be a man of science and can get quite technical. I do have experience growing in soil, mostly from being around outdoor growers for most of my life but also from having done so myself.
From my own experimentation in the grobo, this is what worked for me (and wasn’t hard to try):
Unplug bottles #1 and #2, as the second bottle states it’s not to be mixed with what is about to be added. Bottle #1 won’t be much use without #2 anyway. This also can help to avoid undesirable “pH swings” early on in the plants’ life.
Make sure to be filling with distilled water (not “spring water”, it must say “distilled water” on the bottle). It’s already close enough in pH to what these plants like, I’ve found it possible to grow without pH up and down when using this water.
To “get rid of” the rot, when doing a drain/fill, add about 0.5mL/L of bleach (yes, just regular bleach not scented or anything, Clorox plain) to the res as well, so about 4mL total.
I’ve used upwards of 5-10mL when it was really bad (during a “save”) though that was only for 6-8 hours and was outside of the grobo in a makeshift “ER”, basically a small bucket+air pump+humidifier in the corner on a table while I cleaned out the grobo reservoir with bleach (instead of vinegar) to re-sanitize.
That alone has helped considerably for me but I do not feel comfortable recommending that anyone actually tries this until I’ve seen it work through to the end. I saved my 3rd attempt this way after losing a 2nd one to root rot around 1 month mark; I tried hydroguard among many other things which just weren’t working in my environment. This last time I just said, “I’m going to try another solution from that other growing forum” and sure enough it has been more successful (and cheaper) than the recommendations here.
Your mileage may vary, I just hate to see other plants falling victim to root rot and the same recommendations being made which didn’t work in my case or were quite undesirable (like using a water chiller as that comes with a greater risk of flooding).
I had thought about buying Dutch Master Zone instead of Hydroguard for my environment, even though the latter is what everyone here recommends, because its magic ingredient is said to be chlorine and it is said to work when hydroguard didn’t.
Also - using hydrogen peroxide instead of bleach might seem to do the same thing, but for me it only lasted a week and then the root rot began to like it and took off like wildfire. I was re-applying it within 48 hrs and at first it seemed to be working, until it killed off enough of the beneficials that the bad bacteria used it as a launch pad (and food) for their next attack.
What I do is take a whiff (smell) of the water with the res lid cracked a bit, and if I notice the slight smell of chlorine is gone I re-apply another 4ml (roughly every 3-4 days, sometimes sooner). It dissipates from the water usually within 24h. Once you see that it’s in check, i.e. the rot is no longer growing and has basically “gone away”, just drop that dosing down to 2mL per drain/fill and it should stop it from reoccurring.
Another thing to note is that I haven’t yet started this from the get-go, i.e. from seed, so I don’t have good figures for how much to add and when for a new grow. I’ve only recently managed to save a couple plants using this method and will update this thread when I have more information.
I have recently switched to using pool-grade chlorine instead of bleach to eliminate the “extra stuff” (suspension material) that comes in bleach from being added to the reservoir; though from what I’ve heard and seen is no big deal anyways. I don’t recommend this to everyone, as this is much more concentrated than bleach and can be dangerous if not following the proper handling procedures. It was only $15 and should last me years if it works, though, so I’ll let you know how that goes after some more time has passed.
A cheap $20 pH pen (plus a calibration kit) is worth the investment as well, to at least double-check you’re in the right ballpark (pH/EC) when doing a fill. Everyone says to buy the expensive ones, but I haven’t yet - am holding off on the hopes that the grobo team exposes our data to us as I have two expensive ones already sitting in the reservoirs (as I own 2x grobo units)!
Also keep in mind that my intent is not to “cheap out”, but also not to over-invest where not necessary to. As others have outlined, some of us weighed the value of purchasing these devices (humiture module, ph/ec probes, atmel device to drive them, related switches/modules that go with that, etc) against the cost of a grobo and saw the grobo as “about twice as much, but we get it fully integrated”. I was sadly mistaken when I unboxed my grobo (more than 30 days after purchase due to being out of country) and set it up only to discover how closed this platform actually is! It was disgusting and disheartening to give an idea of how I felt that day, but I couldn’t send it back and basically had to make it work at that point.
My expectation when purchasing was that much of the data visualization and presentation that I would’ve had to develop (or setup from opensource examples) myself would be provided, i.e. “THAT” is what I expected from the app. Instead, it was the exact opposite with little to no data being displayed with that not-so-subtle boxed-in/proprietary feel. I fear for the longevity of the platform should another company step in with an API-first mentality and win over those such as myself who expected as much from this product.
The reason for outlining the expectations and deficiencies in the last part of this post, is that a lack of access to that data makes such experimentation (as described in first part of post) much riskier than it should be. The thought did cross my mind to write a script to send in a ticket to request my data from support once an hour, and to parse their response to put in my own database, but really?? I’m sure that’d get old rather quickly (and be subject to huge delays/gaps in data) and is not really something I’d actually do but does illustrate how painful it is to some of us “advanced” users, especially when posed with problems such as I’ve experienced.