This is what I feel is important to pass along.
I see no reason why a method, and in this case, a nutrient enriched sediment should have limitations placed upon it, when those limitations can be overcome by enhancing the method to fit each persons goals. If no dosing is your primary goal then its important to understand the limitations based on that goal. If the primary goal is to be able to grow any species you want, then a routine would need an adjustment. And understanding that if you do chose to dose, and dose at a level that brings success, that you should not fear negative effects in the causation of algae, nutrient balance (after all none of us measure the nutrient uptake from the soil itself so that argument is null), etc. But we shouldn't place our failures on others based on our goals. That should be left up to the individual based on their needs, with all the available information at their disposal to make their own decisions.
Yes, well put.
My gut has told me that the limitation in the water column is a primary causation. If a plant is lacking roots then where is the uptake of nutrients going to come from until roots are established?
I'd be more careful here.
When you have a new set up, the leaching rate from the soil will be high, so there's a low level continuous release of nutrients.
To address that issue, which is typical in flowing systems, and even if the No3 is at 0.25ppm, far beyond the detection limits of most test kits in the aquarium trade by 5x, if not more.........is adequate to prevent limitations.
So while some might assume there's no impact because their cheap method does not detect N in the water column, it does not imply there is none there.
This is a common situation in natural systems where we test and do research.
You cannot say too much without addressing that and the lower levels of leaching, etc.
This range is a common ppm for Florida springs for example, where there's no nutrients in the sediment, but a very low, but continuous amount in the water.
This seems to effect some species rather then others. I'm sure this has to do with nutrient transport and storage in varying species, and also that some species may require a minimum level of water column supplementation in order to survive.
But all species, as far as I know, do pretty good with water column alone. The water column extends down into the sediment for root uptake and vice versus.
Unless you scrub the water column clean, or isolate the root zone, you cannot avoid some of each method location occuring.
Sediments such as DIY MS also are pretty variable I'd say. no one test their soils for N or P content or leachability.
So there's a massive amount more guessing going on here than with say water column, which is easier for hobbyists to measure.
My point here is is that might have much less to do with the MS, and a lot more to do with the various N and P etc concentrational differences between MS's from each person.
You, nor any of these folks have ever bothered to test to see if the comparison's are even fair. I have measured the delta clays I use......, they are typically rich in P relative to N(3:1 to 5:1 ranges N
), but we see little N limitation since the water is loaded with N........
Thing is, folks using MS assume(most from what I've read) that all the MS used are equal/the same, that cannot possibly be true, so what are you really comparing here?
Apples and oranges?
It's a bit like the old light arguments, using a light PAR meter gets around that.
W/gal really does not. With ADA, we found a much lower than expect ranges........which led to some bad conclusions, on everyone's part, mine included, but.......I bothered to test and ask the question and see.
Same thing here, you have to ask the question, see, test, and confirm, otherwise you will get into trouble.
Perhaps there are some back door methods to get around of it.
I understand your approach towards a balance in both locations. This not only approaches limitations, but also allows the plant to optimize uptake by having availability in both locations. Is there a noticable/significant energy savings in nutrient transport in a dual availability system?
I think Ole and myself and most aquatic botantist would argue yes.
Then again, it might depend more on the plant in question, for Egeria? Hydrilla? Nope......Erios or Tonia? Perhaps.........
So generalizations for weeds is likely okay, but for more specific species?
No, I think we cannot say unless we do the testing.
If the goal is no water changes then tailor your dosing to meet that need. If the goal is less water changes or a prolonged time period between changes, then make those adjustments. I see there being alot of flexibility here while still having success with this species or others.
Yes, I do as well, for any of these goals. I would caution as to being so inflexible as to not try either case(no water column or trying the water column as well as MS). The trade off to add water column ferts is really reduced once you add a rich sediment, because you have a back up for each of the two locations, so you can run things lean in the water column, avoid water changes, or do them and dose richer(or stick with lean, your choice).
In most all cases, adding a richer sediment will make dosing much easier and supplying nutrients easier.
You cannot argue that point.
If you skip dosing the water column, this makes things much easier and forgiving.
You cannot argue that point either.
If you make the assumption that there are preferences in root vs foliar uptake of specific nutrients, then adding them to both locations will address any such issue.
Both cases are met there either way. You cannot argue that much either.
These are all safe assumptions.
Unsafe ones assume that things like water column dosing is "bad", " is "hard", "causes algae outbreaks or leads to their encouragement", that their is a lot of importance on nutrients/dosing, all MS's are the same, water changes are "bad", not doing water changes is "bad", "testing is bad".
I think more reps are required to make much conclusion as to specific species of plants. People use to say these same things not that long ago about water column dosing, but we later saw it was more due to light/CO2 issues.........
I see no good reason a plant cannot do either location as the principle location.
They are opportunistic. And it's much easier to add a lot of nutrients and keep them there for very long time frames with enriched sediments, MS, ADA AS etc.
Tonia and R macrandra do excellent in ADA AS.
We know that. I know that R macrandra does well in MS, I have not tried the Tonia, but I see little reason to think it would do poorly.
Root growth and establishment is heavily dependent on CO2/light intensity, so if those are well met, then the plant has plenty of resources to make roots and add ample O2 to any type of sediment, but the % OM should be no more than 10%.
That is likely the issue with some MS's(OM %).
It's A SIMPLE test to do for a lab.
But for the cost of that, you could buy the ADA AS.........
So that's a trade off.
Too little OM %, then you do not get the benefits.
There's many unanswered questions and unknowns here.
Running down the species listings is tough, folks have had many theories(some still do depending on their own personal success with various methods). If some one cannot grow P stellata in flourite, is it the flourite's fault?
I do not think it is.........likewise, the ADA AS?
We have examples of both, so we also need to look for examples where folks have grown these suspects in MS and had success.
Then you focus on those systems for answers.
Failure to grow well/do well does not imply you have had a good testing of the MS. If you have good growth, then you know it cannot be due to the MS......
This is how you approach the test method here, not through failure, it might be you failed elsewhere, so the test was dependent on something else overlooked, not considered etc.
So you try and falsify your hypothesis that R macrandra does poorly on MS.......
That's how I would go about it.