Plant specific substrate vs inert. Advantages?

I do not think the "preference argument" is valid nor correctly applied when folks suggest it.

Do I want a larger Crypt or sword plant to begin with?
Start with the goals you want there.
Few folks want ominous massive plants.

Adding more will produce faster growth folks often claim.
If you are adding enough water column ferts, these plants should have no issues at all!

The problem is and where folks louse things up: they do not add enough water column ferts and the plants do not look that good.

When they add a fert tab under the plants, which use up a lot of ferts as they get larger, the weeds take off again and color up. No one seems to bother testing and makes these assumptions about them.

Why else might Crypts and Swords, both fast growing plants after the root's which have a lot of structure and therefore resources added unlike say Rotala............make such root systems?

Is it for nutrients?

Why then..............do these same plants also prodice massive structures in inert soil also? With good water column ferts?

Consider where these weeds are found.........streams and rivers...........what happens there every year and season?

Flooding and water level changes.

So you have two issues here.
One is the shear force due to friction ripping the plants out of the sediments.
They need strong roots to hang on!
The other issue, what happens when the water level subsides in the dry season and the plants are left high and dry on the banks?

No water column then!
So they need root then!

Aquatic plants are almost all opportunistic, they will get nutrients from where ever they can.

Never forget this.

Aquarist seem to want to believe all sorts of muckery.
I'm not sure why, the research suggest otherwise as do the folks that work with aquatic plants in the field etc. Aquarist do not set up isolation experiments to test their claims with respect to sediments. I've never met one yet.

But they often suggest because they add a tab under their sword or it has big roots, that the plant prefers it. There is not one paper that shown this to be the least bit true.

I think if you step back and consider our habits as aquarists, the plants and their growth rates and biomass as they grow, you get a much better method and clearer picture about what is occurring there.

Why "either or", "one over another"?
Such black and white thinking is bad in life as it is here.

Since we sometimes remember to dose the water and the sediment method also works well (this applies to both non CO2, Excel and CO2 enriched systems BTW, but not most Marine systems), why not use both?

This extends the utility and time for the substrate and depletion rate/time of both sources of nutrients. So you get more out of the water column and more out of the sediment.

I've been saying this for a decade.
Folks still do not see the usefulness here for some reason.

As far as adding ferts to a sediment rich tank and getting algae, how can this be due to the water column ferts when we can add ferts to an inert system and not get algae?

You need to answer that question before you suggest that leaner nutrients in the water column are the causes for your algal issue.

I can add 50ppm of NO3 and 5ppm PO4 and 2 ppm of Fe, even 5-6ppm and not have any algae.

Likewise I can grow plants in sediment only with no nutrients at any sort other than gases like O2/CO2 in the water column.

No algae in either case.
You cannot blame either method for your algal issues.

Good healthy plant growth defines the system, not nutrients.
We have more than method than can integrated together synergistically.

Regards,
Tom Barr

 

Very true, how fast do you want to grow plants?

Some like the faster growth.
Most really do not once they get it and after 1....2......20 years of hacking it back, tend to think otherwise.

Dosing is "easier" no matter how you slice it with macro enriched sediments.
It does not imply as many seem to assume that you have to dose less to the water as a result...........it just means if you do not, you can still get away with it as the weeds still have a nutrient source at least.

Likewise, an inert sediment works if dosed to the water column.
You should be able to get good similar growth rates for each method if you are consistent.

However, the easiest method given our bad habits...warrants the water column + sediment sources for nutrients.

Stick with that approach.
That applies well to CO2, Excel and non CO2 methods.
High and low light etc.

Reconciling the methods, namely non CO2, Excel and CO2 is a goal I have and to help folks see the usefulness for each method given the hobbyist goals.
Things still work the same, just the rates are slower/faster different.

Once you have that in mind, then you can see how they are all very similar.
Then the advice is not as different as you might think and the trade offs make keeping the tanks much easier to understand.


Regards,
Tom Barr