I have been playing with this immensely (I am on vacation). I stumbled across some appropriate ratios for nutrient uptake.
I have been adjusting my values:
Nitrate = 15
Phosphate = .5 ... just got it up to 1 prior to lights for absorption.
Kh = 60
GH = 100
pH = 7.0-7.2
That is the light: The Lumen per square inch is 14.6 ... I did the calculation. This does not account for penetration/refraction/reflection etc.
I have learned a few things that I will share (you may already know them but correct me if I am wrong):
1) Plants require 3 major macros to live: Potassium, Nitrogen (in the form of nitrate), Phosphorous (in the form of phosphate).
1.1) The ironic part is that prior to planted tank all of these things are deemed bad to have ... now we actually NEED them.
2) The ideal ratio (according to Barr) is 7:1:10 ... Nitrogen:Phosphorous: Potassium ... provided you have a high tech set up that can actually uptake ALL of these nutrients --> The nutrients may be used up if algae decides to grow
2.1) the algae will ONLY use the nutrients that the plants CANNOT use (because they are limited by a specific macro/micro nutrient) ... in other words, we can beat algae growth by simply growing plants and correcting our dosage ... which also changes based on the flora in the aquarium and growth/trimming routine.
3) The things I was noticing are signs of potassium/iron deficiency (ironic because I have Seachem Flourite substrate - but that doesn't matter ... see 3.1); however, I started to notice leaves turning translucent and falling off --> the plant is metabolizing its own leaves to provide NITROGEN to the new growths.
3.2) Plants uptake nutrients in 2 ways: substrate + water column ... if there is iron in the substrate but no roots, it makes no difference - an iron deficiency will occur (as I noticed in my Pothos plants sticking out of the water).
3.3) So I decide to increase nitrates, that forces my other nutrients to then go out of balance --> if we over dose EVERYTHING (seems like a logical response), then the plant can't keep up with the nutrients because of limited CO2 ... ok so I dose excel and have no CO2 system ... obviously we have lighting at play here as well --> my light is decent (I think) ... it all has to be balanced, and we need to find that balance.
I will take some photos and send them to you: a cool phenomena has occured on my rotala indica. It had large leaves, then small ones, then after I started dosing, the leaves became big again ...
Also, quite interestingly, my ludwigia in front is near death and the one in the back is actually growing leaves. I'll attach photos.
PS I have managed to find a balance of nutrients, and have a fuzz algae outbreak -- success! This means my "attempt to balance" is working ... and I have found an imbalance, so when it begins to become outcompeted, I am closer to the right balance for my tank.
Iron (I noticed the yellowing of my new leaf (with green veins) on the pothos had to be an iron deficiency).
Excel --> 0.5 ml per day before the lights come on ... should I increase this to utilize my super dosages of macros?
All seachem products.
Any thoughts are nice !!!
The rate this thing is dying is remarkable --> even more neat is that the two tiny leaves on top aren't dead and 2 on the bottom have also not died.