I think if you put on the big picture and common sense "Hat", aquatic plant methods make a heck of lot more sense.
Folks get stuck in the mud and then are left with only contradictions and belief. That does not get you anywhere except good at arguing semantics.
The data looks suspicious to me, it's very rare that you have such data all being so incredibly similar.
Large water changes certain amplify growth and stabilize nutrients, which ADA does and does a lot. So that could help but I know CO2 ppm's change quite a bit every day and they NEVER add CO2 at night.
The tannins in the ADA AS also mess with the pH/KH relationship, so you cannot use that for measuring the CO2 in his tanks.
Some seem to assume so.
What if they measure only the day after a 50% water change vs 6 days later?
How old is the tank and at what stage is the plant establishment?
These make real and important differences and you cannot compare them without addressing such things.
I do the same large water changes for the same reasons.
Take a look at your tank after doing a 60% water change in the morning, add ferts etc right after, then look at the tank after 8 more hours of light.
Now compare that to the same tank 5 days after the water change.
Ferts are not the issue if they are the same.
CO2 and O2 are.
I think it's quite a hoot when someone claims plants do not need high nutrient levels, yet has ADA AS or soil in the sediments.
You cannot suggest that generally and not account for the sediments/soil.
Also, you can have high nutrients in the water, but none in the sediment.
You have to consider both, some knuckle heads seem to forget the other 1/2 of the sources(potentially) for nutrients.
The soil folks forget and claim the water column is bad for nutrients, the Water column side claim that sediment ferts are bad/not needed.
Both groups are wrong.
They should work synergistically together, not opposed.
Fish and plants really do not care, as long as some is there, you gain no advantage by one or the other.
But you do gain advantages by using them both together
Folks space out dosing to the water time to time, so soil is a good back up.
Some seems to assume that leaner is better, so at least they have a back up.
For the general population, sediment ferts are pretty good, but so are water column ferts if they can add them consistently. Folks should dose routinely and also do water changes, that part of ADA is NO DIFFERENT.
But this way, you have a back up.
After testing ADA's line, that's what I've seen and concluded and told folks.
Many of the ADA crowd seem bent to promote Amano's word, rather than testing and "learning". Seeing if there is any interaction between powersand and AS in terms of growth. Seeing what is actually in the ADA liquid ferts. Seeing if Tourmaline, Penac, iron bottom, Bacter etc are really helpful and if so, what is it they really do and why, is there any real support that we can discern? If, not, you cannot say anything. Some of these same folks are really into supporting testing as well with NO3, PO4 test kits etc.............all to "learn". Seems a bit ironic to me.
Regards,
Tom Barr