Rubisco is not a P sensitive enzyme for an obvious reason: it has less P requirements and most plants are well adapted to low P, if you have no N, you are in serious trouble however.
Low P will have much less impact on growth than will low N.
I do not think there is any less issue or more with algae if you keep things lean or not, because none of these idiot's know a thing about algae or how to measure, test and show that they are really limiting algae at all.
I get sick of them claiming this crap to tell the truth.
They make claims and do not support them.
Sounds nice, but it's not true.
Inducing algae is how you see and learn more about it.
It's not the least bit true in research data on tropical or subtropical lakes.
The research suggest there's NO PATTERN.
See Bachmann's reference for proof, not speculation.
462 lakes where measured and considered in the study.
Algae limitation studies from Ulrich also shown that P limitation was been resolution of even the best instruments.
Now if they cannot show it, how the heck can a hobbyists?
Get real.
I cannot do it either.
So how can they even say this?
The "power of belief" and/or ignorance?
I've already mentioned this many times over the years, so the info is there and available to hobbyists.
Naman, you are very correct about C and N and P linked together(light as well).
If you limit P a great deal, then you will reduce CO2 demand, and N.
Likewise if you strongly limit N, you also limit CO2 and P demand.
Plants have a good amount of storage of N and P, but not C really.
It's just needed in too large amounts in small weedy plants.
Aponogetons have extra etc, but most plants do not.
Yes, you need more Rubsico at lower CO2.
So a plant in a non CO2 tank has more Rubisco per unit area/DW etc than that of one in a CO2 enriched planted tank.
So you will also see more N per unit dry weight in the non CO2 plants than those of the CO2 enriched system.
Now if you consider this, then the ratio of N goes down in these plants, so a ratio of 4:1 N

is fine whereas in a non CO2 tank, 10:1 might be better.
ADA also started adding PO4 to the liquid ferts
after I started suggesting this back in 1997. SeaChem and others had been as well.
As far as ADA vs EI etc, the real issue is consistency. If you add ferts to the sediment and lean ferts to the water column vs rich ferts, to the water column, you get the similar results...if you are consistent.
Most of us are human.
So try ADA Sediments + EI.
Then you have the best of both worlds.
Not one or the other.
Sediment ferts are easy.
That is why ADA system is so good, it's not too much issue to mess with it, folks used soils for many years with good results also.
But telling folks to do water changes 2-3x a week for the first 1-2 months would help improve things there as well.
Also, larger grain sizes vs mud also helps.
So there are reasons why it works well, not some miracle.
As far as lighting, you can simply grow plants with low light without a noon day spike as well, and they do nicely.
If you drive the tank faster all day, well, then it's a high light tank and needs more CO2 etc.
But nothing stated suggest algae are ever limited in either tank.
There's just no such evidence.
EI is just a concept, using water changes to flush, ADA uses it as well but does not justify or use empirical data. These where both independent.
Using just the sediments, nothing I've said has suggested adding ferts there would hurt. So it's using ADA's sediments, I can use other things, like sand + mud.
But ADA's looks nice and easily to handle.
I like one homogenous material, not Powersand etc.
ever asking why it works anymore - they simply use it.
Yes, that is bothersome and disturbing, the faith based approach to plants
I think you need to really consider the effects of rates of growth, time of lighting and they interact together.
The less light= less CO2 demand.
That plays a massive role in algae.
Stable CO2 levels allows good production of plant biomass.
the PO4/NO3 are not that limiting , they are fairly rich and always available, if not by the water column, then by the sediment.
This way you benefit from both rather than one or the other.
Aquatic plants are opportunist.
So the big picture should make sense to you as well.
Lower light overall
Less CO2 demand
Moderate growth rates(less work)
Less N and P demand (allowing for translocation if too lean in the water column)
If you have high light(typical american tank)
Higher CO2
Higher growth rates
higher N and P,
Which is more likely to crash or be less table?
Clearly the tank with high light.
It all starts with using less light.
How did you think Amano figured that out?
He uses lower light, look back and ask him yourself.
The higher lighting is something he's added in the last decade or so to amplify and have more growth, color density etc
And that's also when he realized he has to add more water column ferts(N and P), Green brighty "Light" and "Shade".
Regards,
Tom Barr