First, good news--despite my failure to find SAE's that I can afford, since
I started the DIY yeast CO2 and switched to Flourish, most of my hair algae
seems to be slowly disappearing.  It gets pale then goes away.

Now, the question.  I have the wonderful good fortune of having a water
plant manager who answers my water questions via email, usually within
hours.  Among the recent questions I asked him was whether they measured
phosphates.  His answer:

  Yes, we monitor phosphate, so as to limit
          corrosion in the water system.  Orthophosphate is held at
          approximately 2 mg/l.

Could someone tell me what this means?  Is this good or high.  If high,
what do I do.  I've read somewhere that excess phosphate can render
(liquid) iron fertilization nearly useless.  Is this true?

Department of History
University of Iowa