UV and iron

My UV has been turned off for three days now, and the carbon is long gone,
but my iron still isn't up to the 0.25mg/l mark despite daily iron
additions (1/4tsp 7% iron chelate).  This may mean:

(a) I need a new test kit.
(b) The plants really are using this much iron (perhaps the Giant Val
    that grows a foot a week in the corner of my tank is responsible).
(c) Exhausted laterite in my substrate is stocking up.
(d) Something else entirely.

In any case the experiment is going to end soon as the plants are starting
to show deficiency symptoms.  I'll try again when I find a balanced
micronutrient mix.  Maybe I can trade one of the kids in for a month's
supply of Dupla...
Kevin Conlin   kcconlin at cae_ca   "We're Canadians.  We HAVE to be polite"