My anubias, swords, and Java fern have been growing wonderfully for a
couple months now. I have been using Flourish and Trace, more or less to
package directions. Lately, my anubias has been turning a reddish-yellow. Is
iron deficiency likely? None of the local LFS have iron test kits, in fact
most of them have no idea what I'm talking about. Mail order only option.

75gallon
moderately planted, heavy bio-load, gravel sub, wet/dry sump overflow.
3x40 day-max 1x40 something else, yellowish light. Forgotg
amo:0
nitrite:0
nitrate:10ppm
Ph:7.0
tmp:78f