All I have to do is look at about dozen tanks I've done, and 100's that other's have done with plain sand.
Aquatic plants are opportunistic, they will get nutrients from locations, it also is important to specify which nutrient as well.
So if you add very little to the water column, and add a rich sediment, of course, the plants have little choice
Any beginning plant science person would tell you that.
Say you do the reverse, add nothing to the sediment, but add a non limiting solution to the water column,
modified Hoagland's solution etc is a standard method used in plant science for this non limiting solution used in growth studies.
Then you compare the rates of growth.
They will be slightly higher with Hoagland's.
Now Hoagland's has NH4, we do not like to add that to the water dcolumn for a few good reasons.
The ADA crowd never tests, anything near as I could ever tell.
They do not set up test where the plants still have fertilizer available for the other case, where plants have access to water column ferts like the sediment.
You have to compare them on equal terms for any test.
Have a control, then try ADA AS + water column ferts(lean vs rich etc).
Not one of them appears to have ever done that other than myself.
So ignorance is hardly the measure of knowledge and experience.
You can claim all day long, but unless you have set up and done a well out test, and your results support your claim, it's not much more than belief.
Suppose you are limiting plant growth with say PO4, how might that affect things and your belief when you add PO4 suddenly and you get algae bloom?
Why might that happen?
If the CO2 was low to begin with, you did nothing else, and added PO4, that switched one limiting factor PO4, to now CO2.
And we all know what happens when you have low CO2 suddenly..........
However, if you make sure CO2 is high for both cases, then you do not get the same response.
Simple controls are very very rarely done in this hobby.
Low growth can be easily achieved using scissors
That's what ADA does, and that's what they do at AF and that's what I do and have for decades.
It's called pruning.
HC builds up and needs pruned.
Less light= less growth= less frequency in trimming.
If you have mild limitations, you will have less growth also.
Less light, less CO2 etc etc.
Many variables these folks rarely , if ever, account for completely.
You can still have a nice tank, make claims, and have absolutely no clue about plant growth or the parameters inside your tank also.
I'd prefer not to go that route, I like to know why and be able to explain most of the variation in observations based on a sound model of plant growth.
You can measure height, but you need to set up and proper test to make the claims they do.
HC grows very well in ADA, it does well in mud and without any water column involved at all, most aquatic plants can grow well without water.
Yet we see plenty of cases of HC and Gloss being grown nicely in plain sand.
Maybe it's the grower and the water column dosing, rather than anything to do with plant preferences.
Regards,
Tom Barr
