Hey Barr Report,
Let me cut the the chase, I have a 5'x2'x32" aquarium holding approximately 700L.
My Specs are as follows:
Lighting: 3x 125W HQI (High Pressure Mercury vapor) Downlights (12 hour photoperiod)
Filtration: 2x EHEIM Pro 3 600
CO2: Milwaukee Controller + Regulator (Splitter regulator, An atomizer running on each cannister for even diffusion)
Substrate: 2 inches of Aquasoil capped off with 2 inches of inert Black gravel.
18W UV (Inline)
1x Hydor 300w heater
Water Sample as Follows:
K - 20ppm
CO2 - 80ppm (La Motte Titration)
KH - 6.5'
GH - 10'
Ca - 40ppm
Mg - 20ppm
PO4 < 0.05ppm
Fe - 0.5ppm
NO3 - 15ppm
When I first set up the aquarium, Everything was all well, The plants frequently pearled and growth was at a fast level that Id expect.
Slowly the aquarium went downhill and the scape's growth halted. Mainly due to the fact that I got lazy and slacked off on water changes and dosing.
I did a rescape with a new layout and once again began testing Elements and adding as I needed them on a proactive basis.
For my effort I was rewarded a brief period of pearling but now has diminished once again to poor growth For whatever reason.
I water change once weekly 50% or more, Dose API leaf zone according to the bottle, KNO3...GH(Mix of K,C,Mg salts).
Now correct me if I'm wrong, But I am led to believe some plants e.g. Certain (for example) Aponogetons among many others have large surface areas and adaptations to cope with nutrient deficient waters in which they live and as such, When they are supplied with excessive amounts of phosphate in Particular (say >0.5ppm) Growth becomes irregular and appears as Holes in the leaf, poor growth ect. The idea is that some plants cannot regulate Their phosphate intake and as such cause's "Hick up" in cellular/metabolic reactions.
I have been told also that some plants for example stems are subject to conditions with reasonable phosphate levels and therefore do much better as they grow faster and need the phosphate on a regular basis if maximum growth is to be achieved. (Liebigs law)
So on trouble shooting this issue previously I places lanthanum based "Phos-out" pads in my filter. I did however notice my Nuphar Japonica which died off previously (Apparently from high phosphates) come back from the Rhizome after my the phosphate pads had removed bulk of the phosphate. Mere Coincidence ?
And I am having no issues with algae, Only growth.
(Perhaps only mild algae on the plants that are not growing)
So finally, I would like some insight into what people think is limiting growth ?
What should be changed or corrected, am I correct to hold the above Statements as correct ? Is there any documented study's on phosphates Reducing growth.
Here is the link to my tank journal if you would like some more information: