Maq's Substrate Experiment

[_Maq_]

I'm considering a new experiment, and there are some points I'd like to get your advice about.

I want to check behaviour of a "typical" aquasoil compared to sandy substrate, and a sandy substrate with and without "typical" root tabs.

Some of you already know my experimental workstation. I imagine I'll establish these four tanks completely anew, lay down the substrate, run a dark cycling for four weeks without WC, then a big WC and introducing some plants. As always, without CO2 injection, without filters, only power head. Water changes 50 per cent weekly (or so), always adding water with constant mineral composition. (I tend to dose lean and keep water soft and acidic.)

Regular checking of temperature, conductivity, and pH, and comparing the health and growth of plants. I hope the experiment will show/suggest something interesting on (dis)advantages of aquasoils, nutrient-free substrates, and root feeding.

You're warmly welcome to comment on any aspect of the experiment, but above all, I need a feedback on these questions:
(1) Is ADA Amazonia the typical representative of all aquasoils? Is there any other one, more typical, more famous, used more often, or anything like that?
(2) Is Osmocote the first choice, the typical representative of root tabs? Is there any other one, more typical, more famous, used more often, or anything like that? (I've noticed that Osmocote is sometimes hard to get. Any similar alternative?)
(3) Is it worth the effort including one more substrate, namely one of those porous ones (lava rock) which supposedly maintain the substrate better oxygenated, provide more colonization area to microbes and so on? Or anything else?

I've got four tanks. One is sandy substrate, second is sandy substrate with root tabs, third is aquasoil, and the fourth is open to suggestions.

Thank you.

 

[PARAGUAY]

Well try that maybe lava substrate with just lean fertiliser ,looking forward to any conclusions

 

[hax47]

Hi,
Would it be possible to ensure the same water column nutrient levels and pH? I expect both the Amazonia and the root tabs to leach nutrients into the column and Amazonia to affect the pH to some degree. You will likely have more variables here than the substrate difference only, and that could make the interpretation a bit difficult. My approach would probably be an overload of nutrients instead of lean dosing, so leaching would not matter that much; as for ensuring the same pH ... I don't know how that would work in soft water ... maybe with constant KH adjustments in the Amazonia tank?
In the 4th tank, you could have a bare bottom, no substrate, and plants attached to something to prevent uplifting.
Also, will you have any habitants and addition of any organic matter (e.g. fish food), will you remove the dying plant leaves? The organic matter in the sand could accumulate and make it a different fauna for the roots in the long run (depending on how long you plan to run the experiment).

 

[_Maq_]

Would it be possible to ensure the same water column nutrient levels and pH? I expect both the Amazonia and the root tabs to leach nutrients into the column and Amazonia to affect the pH to some degree.

That is my expectation as well.
But I don't intend to adjust water to this. Changing water column contents is part of the effects of these substrates. I don't want to negate it by changing parameters of the water which I'm pouring in through WC.

You say that you'd overload nutrients to make the differences less pronounced. I think differently. Lean dosing in the water column means that the tank with sandy substrate will get limited amount of nutrients. I'm curious to see whether plants can actually benefit from additional nutrients provided by aquasoil or root tabs.
It is widely accepted fact that Amazonia scavenges bicarbonates. But what if the source water is low in bicarbonates on its own? Will Amazonia push pH extremely low? I'd like to know.

 

[hax47]

That is my expectation as well.
But I don't intend to adjust water to this. Changing water column contents is part of the effects of these substrates. I don't want to negate it by changing parameters of the water which I'm pouring in through WC.

It makes sense, but then you cannot tell apart if the nutrients in the substrate at the roots or the different nutrient levels in the column make the difference. This setup might not be different from experiments when two fertilizers are compared. Maybe you could plant duplicate plants in sand inside separated parts of the bottom (e.g. pots, or bottom separated into two parts ) in all the tanks? That way, you would have the same water parameters, but two identical plant samples in two different substrates inside the same tanks. That would make Soil/sand, sand/sand, sand+tabs/sand aquariums. When running experiments, most often the selection of the right controls limits the conclusions you can draw.

 

[dw1305]

Hi all,

When running experiments, most often the selection of the right controls limits the conclusions you can draw.

That is really the problem, the <"unknown unknowns">.

<"Fully factorial"> planned experiments are problematic, mainly because of the <"large number of variables"> and not being able to weight these, basically we still don't know what is <"the coffee and what is the froth">.

I'd suggest a different approach, where <"we use probability"> and models, based on any data we can scrape together.

cheers Darrel

 

[hax47]

I agree, in biology, there are so many unknowns that we can not control. The usual approach in biological experiments is to change one thing only between two compared samples to minimize the effects of the uncontrolled variables. Still, changing one thing only is not always easy, as the example shows. Because of this, the difficulty is, how far one should/can go with the probabilistic/Bayesian thinking when concluding, to be still correct most/some of the time.

 

[Andy Pierce]

Might be tricky to do, but for the 4th tank I'd be intersted in "used up aquasoil" - aquasoil that has been in an aquarium so long that all the goodies have long-since leached out. I'm interested because that's the substrate of both of my tanks and I'm wondering whether the semi-open structure of the aquasoil balls has any impact on plant growth vs. more compacted sand.

 

[Wookii]

Subbed - interested to see your results @_Maq_

Perhaps a fourth substrate could be a sandy substrate with a high CEC sub-layer - aquatic compost or peat pellets or similar. It would be interesting to see if that is of any benefit over plain sand or not.

It makes sense, but then you cannot tell apart if the nutrients in the substrate at the roots or the different nutrient levels in the column make the difference.

I agree with @_Maq_ that he should keep nutrient dosing the same in all tanks to eliminate that as a variable, but like you I'd be interested to see how much of the nutrients will make it into the water column - I know @_Maq_ has measured nutrient levels in the water column before, so it might be a good variable to test for this time around also.

 

[dw1305]

Hi all,

The usual approach in biological experiments is to change one thing only between two compared samples to minimize the effects of the uncontrolled variables

I'm not arguing, if I had an infinite amount of time and money I'd set this up as a fully factorial experiment and analyse it using ANOVA. I'd still want to plot everything, because <"I'm obsessed with graphics"> (and <"penguins">).

Because of this, the difficulty is, how far one should/can go with the probabilistic/Bayesian thinking when concluding, to be still correct most/some of the time.

You would still need to keep refining your model, but over time you should get nearer to separating the "important" from the "less important", the coffee from the froth. Since I've spent <"more time with ecologists">, I've begun to appreciate their approach more.

As an example I was pretty sure that the <"traditional linear view of nitrification and cycling wasn't correct">, before we had access to techniques that allowed us to search for the genes involved in the <"oxidation of ammonia">.

cheers Darrel

 

[hax47]

I'm not arguing, if I had an infinite amount of time and money I'd set this up as a fully factorial experiment and analyse it using ANOVA. I'd still want to plot everything, because <"I'm obsessed with graphics"> (and <"penguins">).

My former PI used to say that ideas are cheap... it is easy to give them when it comes to experiments, but then someone has to perform them; those are expensive, labor- and otherwise. There is a Hungarian phrase, not the most accurately translated, but maybe even better describing the thing: Beating the stinging nettle with someone else's stick. The original version sounds a bit more harsh, meaning acting at someone else's expense. When it comes to aquarium experiments I need to perform, I get sloppy and reluctant to go beyond what is still enjoyable (like repeating the experiments enough times to be able to analyze them statistically). And I tend to go more creative when someone else is experimenting...
I guess I am already off-topic here; sorry @_Maq_ for that. I am curious to see the results; I am also trying to decide between the sand only and sand + pond soil for my next aquarium.

 

[_Maq_]

It makes sense, but then you cannot tell apart if the nutrients in the substrate at the roots or the different nutrient levels in the column make the difference.

An important caveat is that I don't perceive this experiment as predominantly targeted on nutrient levels. At least not directly so.

This is generally on establishing a new tank. We all know that it's quite a complex and difficult process. There are different approaches to this undertaking. Many people tend to reduce the issue with plants to providing nutrients in ample amounts. Therefore - root tabs. Others use porous substrates (pumice, lava rock) for their purported pros - colonization area for microbes, improved oxygenation, resilience to clogging and therefore "nutrients can freely flow to the roots". Still others like aquasoils for their CEC abilities and stock of nutrients. Or for whatever reasons I did not mention.
What I want to check and see is what would happen in the tank during the first few months of its life depending on what kind of substrate is used (in otherwise constant conditions). A general view, not limited only to the effect of lean or rich dosing. I think we are united in belief - based on various reports from fellow hobbyists - that plants can be successfully kept both in rich and lean conditions. I've expended quite an effort in searching perfect ratios of elements; still, I readily admit that plants can usually prosper in very different ratios. I think there are other variables which ultimately decide the fate of a tank. These variables surely can be influenced by the amount of nutrients available, but I believe that the amount of nutrients - within reasonable limits - is not the decisive factor per se.

What do I expect to see and compare? First of all, mortality of plants, and possible causes. We all know that in newly established tanks, loses are near inevitable (CO2 injectors may see it differently, though). Next, plants' health and vitality. Next, algae. More generally, signs of good or bad development of microbial community. And so on - simply anything what we perceive and find relevant for "making a successful planted tank".

I suspect many of you can deduce to which approach I'm biased. After all, my signature says clearly - sandy substrates. Nevertheless, I'm fairly open and curious on this issue. I've never used aquasoil. What if I reveal some benefits of this substrate? Since it's not very cheap (for me, at least), better try in a small tank and compare with my "traditional" method. Similarly, I can't recall whether I've ever tried anything like root nutrition. Some people swear that it makes all the difference. I wonder what would happen if I try. I'm curious, that's it.

 

[_Maq_]

Please, I'd like to turn your attention to my questions in the original post:
Which aquasoil can I use to avoid arguments like "this occurred due to your option for bad aquasoil, not typical for these substrates", and similar. In short - ADA, Tropica, or anything else?
As for Osmocote: I've found a suitable source. They provide Osmocote pills in gelatin capsules. Is this acceptable as "the true root fertilizer"? Any better suggestions?

 

[Wookii]

Which aquasoil can I use to avoid arguments like "this occurred due to your option for bad aquasoil, not typical for these substrates", and similar. In short - ADA, Tropica, or anything else?

Either ADA or Tropica would be fine I'm sure, both are highly regard, and both are heavily loaded with nutrients to give you the extreme end of aquasoil induced start-up issues.

As for Osmocote: I've found a suitable source. They provide Osmocote pills in gelatin capsules. Is this acceptable as "the true root fertilizer"? Any better suggestions?

Hopefully most people on here have been sufficiently warned off using them in that form, with a complete capsule in one spot. When I have used them in the past for tank set-up, I would open a few capsules, and sprinkle the contents over the base of the tank.

 

[_Maq_]

I would open a few capsules, and sprinkle the contents over the base of the tank.

The bottom is 242 by 292 mm net. That's 7.07 square decimeters. How many of those tiny balls would you suggest for this space as "the norm"?

 

[Wookii]

The bottom is 242 by 292 mm net. That's 7.07 square decimeters. How many of those tiny balls would you suggest for this space as "the norm"?

I really don't know what the 'norm' is to be honest, on that kind of size, I'd probably only use a couple of capsules, but other folks may use more.

Incidentally what kind of substrate depth are you going for in these tanks?

 

[John q]

They provide Osmocote pills in gelatin capsules. Is this acceptable as "the true root fertilizer"?

I'd say 2 off these sprinkled within the substrate of a base of 242x292 would be a sensible approach without going OTT. "For test purposes"

 

[LMuhlen]

My only reference regarding osmocote is what was posted in the 2hr aquarist website. From memory, he suggested selecting osmocotes without trace elements, with as much ammonia as you can find, with as little NO3 as you can find. He would recommend one unit per square inch (?). I think that was it.

As for aquasoil, I would recommend Ada amazonia II, which supposedly is more user friendly at startup.

 

[_Maq_]

Ada amazonia II, which supposedly is more user friendly at startup.

Yes, I've noticed the same, but isn't it a deviation from the norm?

 

[erwin123]

As for aquasoil, I would recommend Ada amazonia II, which supposedly is more user friendly at startup.

Maybe because ADA Amazonia II comes with root tabs which you can choose not to add? If you added all the root tabs at startup you might have the same Ammonia issues as other versions?