Richard Sexton wrote:
The question is, are these effects common? I assume it's nothing to
worry about, but it's interesting and obvious enough that you've all
probably seen it. What say?

Souds like low nitrates to me and or low phosphate. Iron is probably
low too.

I dose NO3 so as to maintain tank at 10-15 ppm between water changes.
I dose PO4 to about 2ppm (my tapwater is 3ppm in PO4!)
I dose my changewater (50% change) to 20ppm in K (worst-case scenario
means K at 10ppm, which I doubt)

In other words, doubt I have any deficiencies in macros.

I dose my changewater with Fe to...the exact ppm eludes me, but it's
the standard ppm.
Ca and Mg are dosed in about a 1:2 molar ratio to achieve 3-4 dGH.
Traces come in 2-3x/week in a capful of Flourish.

Net is that if there's anything I'm screwing up it is likely to be Mg++
by way of my arbitrary 1:2 Ca/Mg ratio and 3-4 dGH. Nonetheless, I
don't seem to have any Mg++ deficiency symptoms.

--Trapper