tug

Could this chart represent all of the factors affecting growth rate in planted tanks? From what I've been able to gather there is a generally large range for nutrients that provide non-limiting nutrients for max growth. To me, it seems to cover most planted tank situations. Any thoughts?

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JuliaAdkins

As for all living things, the structural nutrients or macros are the most important to be supplied in regular but not large amounts. The micros are about processing and functioning of the plant and are needed in small amounts.

Diana K

Yes, that sort of bell curve has been used for years to indicate the sort of growth you get from adding fertilizer, CO2, light, and any other beneficial thing (water circulation...)

At the left end on the axis are deficiencies. When you go into the band labeled A, plants die. In area B plants are living, but are not doing as well as they could. The transition from A to B will show discolored leave, distorted leaves (depending on the deficiency) Higher up in B the only sign of deficiency is the slow growth.

Improving conditions as the slope rises into C means the plants are doing better, growing faster.

The fairly flat area at the top is the maximum growth of the plants. If you can keep all the fertilizers etc. anywhere along the top of the curve then the plants will grow at the maximum rate.

Farther right as it starts sloping down you are starting to get into toxicities, and nutrients blocking the entrance of other nutrients. Still in the C band, but the slope is starting down is where water changes may keep things from getting worse. But it may be just a few nutrients are going over the edge, just a few are in excess. Plants will not be growing quite so fast, though.

As you slide back into the B zone the plants will start showing toxicities such as distorted leaves, discolored leaves.

When you exit the B zone, going into the A zone to the right the excess nutrients etc. are killing the plants.

Yes, EI is toward the right side of the top of the curve- plenty of nutrients without getting into excess (water changes keep it from excess).
PPS would be at the left end of the top of the curve- plenty of nutrients, but not anywhere near excess.
Low tech would be lower on the sloping left side- Not quite as much as to make the plants grow the fastest, but not far left (deficiencies). Low tech might be in the mid to upper B zone.

The numbers on your chart will be different for each item you are considering.
If you made a chart for each nutrient (over a dozen elements), and each other environmental thing (light, water movement, even things like trimming) that affects plants you could find a target range for each. Some of these will be best shown on a combined chart that shows how they interact.
If you try to stay to the left but near the top of the slope the plants will thrive, you may have to monitor a few parameters with tests to maintain that careful balance.
The farther right you go the more important water changes will become.

niko

Haha.

That curve assumes that plants require light, CO2, and nutrients only. This is true on the internet and many people follow it. That is why for many years now we talk about deficiencies, algae, stunted growth, shutting down the tank when going on vacation.

What if I said that all you need to live well is food, water, and air? Makes sense, right? Nothing else - stand in a room, breath, eat, drink water. No sounds, no light, no other people, no bed, no chair, no worries. From general knowledge you should know that a human goes insane in such environment in about 3 days. Yes, three days. But most of us believe that aquatic plants will do great with 8 fertilizers, CO2 to the gills (30 ppm), and good light. Hope you start to see how that makes very little sense. If you tell me that plants are not people I'd ask you to not read further because you are missing the main point:

What most of us miss is an endless list of factors that change dynamically and make or break your planted tank. One of them being the microbial population. No, not the biofilter in your Chinese canister filter. In fact you can ditch it right now - a properly setup planted tank does not need a filter. Not joking. Note that that is only one of many factors we never discuss in details.

"Non-limiting nutrients". Sounds so cool, doesn't it? Makes sense too. Except that when a single one of the many other factors on the list I mentioned above decides to act up the overload of nutrients plays a cruel joke on you. Your tank grows algae overnight! I'd show you examples but if I post them here my post will get deleted. So you have algae now and you jump on the internet and ask for advice. What you inevitably get as a suggestion is that you are doing something wrong. You. Not the approach you are using. You are doing something wrong with the light/CO2/nutrients. You can find hundreds of posts on both APC and TPT that follow what I just described. And note that there is never a predictable solution. Other than "You are doing something wrong." 11 years into this "light/CO2/ferts are everything" and no solutions to the old problems. Wow.

So to make this mess simple and enjoyable: Welcome to EI - a good way to run a planted tank in a simple and proven way: Light/Ferts/CO2/Water Changes. Nothing else needed.

ObiQuiet

Alright, Niko, I think it's time I asked you to help with a project I've been thinking about for a long time.

Q: How to capture what we know about planted tanks in a form that people can learn from?

Here's a draft of an interactive map [Example PNG] [Live DRAFT]

PM me if you are interested in collaborating. (Tug, Diana K, et al are welcome too!!)

A way to make the body of knowledge about substances, processes, interactions, and phenomena accessible to people... especially the interactions, causes and effects. Diagrams and explanatory notes can be included as detail where needed.

JuliaAdkins

Great post Niko. Excellently phrased and stated. Thank you so much for your input.