Yes; a very informative article. It states:
plant uptake forces the PO4-3 levels down to zero or only non plant available dissolved organic phosphate (DOP) forms
Which, in my mind, begs the question: do our PO4 tests measure only PO4-3 or will they also pick-up the DOP and, therefore, mislead us into thinking there is plant usable phosphate, when there is not?
Thanks, but this is not about Liebig's law of the minimum - DIRECTLY. However, if DOP is misleading us into thinking PO4-3 is plentiful, when it is not, then that law is violated.
Do any other readers know if our hobbyist grade PO4 tests measure only orthophosphate and not DOP? I could find only one data point that claims PO4 test kits measure only inorganic phosphates. If true, I wonder what organic phosphates do to our tanks. Perhaps it's a good reason to use chemical filters, if there are any that will filter DOP and not orthophosphate.
Another thought here is that we have affirmed that adding orthophosphate does not induce algae. However, I think that organic phosphates do. So, it may be a little bit wrong to say that phoshates don't induce algae. Might be better to say that adding orthophosphate doesn't induce algae.