Nitrate Level

[Ruskull]

 
 
Basically it appears there are other factors, less well understood or researched which appear to be at work. But what it seems to boil down to is that by keeping plants in good condition by not limiting what they need, the algae seems not to be able to thrive. Let the plants suffer and the algae can take advantage.

 
Exactly.  I only have problems with algae when my plants aren't doing well.  
 
Recently I had a huge Java Fern turn brown & "crispy" for no apparent reason.  The taller plants such as Stargrass & H.polysperma are also struggling, but the Crypts and Java Moss in that same tank seem unaffected.  I've also noticed an increase in algae in that tank, primarily the green.  Recent changes to that tank include that I no longer add liquid ferts and I've added a LED fixture to the T5 I already had on that tank.  I still dose liquid Co2 but not as often.  Too many variables to make a conclusion based on what's changed.
 
My best guess would be to lower the light period and resume adding liquid fertilzer.  I would expect the algae to decrease if/when the plants once again thrive.