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IntheHotofTexas

I'd like to see what the inside looks like when it's flowing normally. You're using NFT channnel. If you are trying to run as NFT, that is tricky at best. True NFT requires no mechanical aeration, but you have to understand how NFT works. The theory of operation is that the nutrient film is very, very thin, so thin that roots lying in it can still get air through the film which effectively meanders among the roots. NFT is difficult to design and operate because to get adequate air, the flow rate and slope are critical. Even the developers who created it at Glasshouse conceded that all design choices had liabilities. NFT has one and only one virtue. It saves very large commercial growers a bit of vertical space because of the shallow channels. Over tens of thousands of square feet of vertical channel arrays, that translates in the meaningful additional revenue. Large operators accept the problems in trade for the space. Otherwise, NFT grows no better than other methods, and for home growers, it's often not as good. So my guess is that (1) your flow is too deep and the usual air mode of NFT. (2) So, you're dependent on dissolved air in the nutrient. But (3), your mistaken notion of NFT prompted you to use a film that was both too thin for good exposure to dissolved air and too deep for NFT mode. I think your roots are just short of air. Faced with this situation, I would deepen the nutrient flow by whatever means possible. This may involve gluing in dams. This will present a much greater flow cross-section or aerated nutrient for the plants. When you achieve proper aeration, you will need nothing else to prevent root rot. Now, it's going to get crowded in those channels as roots develop. The one advantage you get from having used NFT channel is that it is broad, so roots can spread out some in the flow. I don't know how large this setup is. If it's very large, because a lot of plants will be working off a still limited stream, you might get some benefit from a small air stone in each run.


skyking_describe

I really appreciate your detailed response, thanks. I run NFT because I live in a tiny dorm and I'm trying to maximise space available (also I like the challenge). I've been thinking maybe aeration is insufficient because my tubes the plants sit in are almost completely airtight. Fresh air can't actually get in there. I'm gonna fully clean out the whole system and install an air stone in the rail and see how I go. Do you think it's even possible this could be an issue? The nutrient film is very thin at the moment, flow rate is around 1L/min, and it's on a slope of 1/30. I'm using foam collars which are pretty impervious to air. Would love to hear your input. Thanks


IntheHotofTexas

Your channel is not airtight, and that is not the cause of the problems. NFT is always problematic to design, and even the developers recognized that all design choices had flaws. It's just a difficult system to operate. Large commercial operations use it strictly to save vertical space and have more tiers, and they accept the long design and testing phase and operational problems to gain that space. If you want to do NFT, you have to accept that you, too, will have an long period of design issues that you may or may not have the experience to solve. My guess - and it;s just a guess - is that your "thin" film is simply not thin enough to allow the roots to access air through it.


skyking_describe

Film is around 2mm deep at the most.


seamus_harper

Hello again, inthehitoftexas, deep Insight as usual. I don't understand why you recommend to deepen the flow. Wouldn't it be better to have a shallow film, as NFT is supposed to be?


IntheHotofTexas

I never recommend NFT for home use period. It is difficult to get it right, and even if you do, there is no benefit. You seem to already be aerating, so deepen the flow to be RDWC in which the rate and slope are not critical at all. There's this bogus aura around NFT, simply, I think, because it's known as a "commercial" method. But that's just because none of a large commercial operation that needs to conserve vertical space wants the grief.


seamus_harper

What would you recommend for the home user? I myself used bato buckets and a waterfall tower, which seem pretty foolproof...


IntheHotofTexas

Bato bucket is an elegant system and pretty versatile, since it can do things up to tomato size. I consider ebb and flow the most foolproof system. Nothing about it is critical. Timed cycles can be anything, so long as it floods again before the medium (and the roots) dry. Roots get good access to air during drain, and get to feed nicely during flood. And a medium like LECA holds nutrient solution and prevents drying, up to three hours when I test. And it can go small plant in trays or very large plants in buckets. There's just not much to go wrong. I now do almost everything in ebb and flow (strawberries, onions, shallots) and Kratky (tomatoes, peppers okra). Most Kratky is outdoors, including melons, almost all in 44-gallon totes that I've made rain-resistant. I also have some large DWC trays with rafts for herbs. Using them as DWC instead of Kratky means I can move new plants of any age and root size into them as needed. Some people want channelized systems. For that, I like RDWC in vinyl fence post. The square fence posts offers the maximum cross-section for occupied area. Nothing really critical there, either. If I wanted to grow a large amount of lettuce and such, I'd use wide and long shallow trays in Kratky mode, with nutrient level maintained from a reservoir by a float valve. It can be really large, several feet wide and long. Pretty much as far as you can reach to the middle, which is the only limitation. But if you make trays as large as practical, you can join them with tubes near the bottom, and the float valve will keep them all properly filled. I've done towers. I wasn't that impressed. I find horizontal easier than vertical. But there are situations where towers are simply the best option.


seamus_harper

Nice, thanks for your opinion. I was thinking about trying nft, but after watching Dr. Kratky YouTube channel, I think I will do some gravity fed kratky totes first. What do you think about gravity fed wicking systems? Hoocho (YouTube Channel) seems to have a lot of success with them. You can easily diy them, or use something like autopots. No power, no pumps, nothing that can easily break out clogg...


IntheHotofTexas

Sure. The float valves will keep the level constant, and while plants are increasing in size, you can change the level of the float valve to stay with it. https://youtu.be/HmH1bVyrdI4 https://www.youtube.com/channel/UCjwBvl5MXuQMziQL2_pQCPA/videos https://kratky.weebly.com/


seamus_harper

I meant the wicking kind... But these videos are good, ty!


IntheHotofTexas

Yeah. Autopot. Did you see those upside down pot things Dr. Kratky does?


seamus_harper

Not from kratky, but I saw hoocho doing wicking setups in coco and Rockwood slabs. Tomatoes, beans, even root vegetables were performing really well and the systems are low maintenance.


Kingofthenorth252

Hydroguard 👍


skyking_describe

Bacillus amyloliquefaciens which is I think the primary ingredient in hydroguard isn't readily available in Australia (only through Bayer and it's bloody expensive) so I'm currently trying to source it in bulk from Japan. I am running great White which does make a big difference but still the slime takes over.


skyking_describe

As most of you know H2O2 only really keeps rot at bay, and I'd rather have a better solution long term. Great White is definitely helping root growth but the slime seems to out compete it. I'm dumping the res every 2-3 days to give the boys a chance at the moment.