One of the things I remember reading way back either in the FAQ or on this list
or both, is that Fe supplements oxidize quickly when added to the water. This
oxidation appears to be partially encouraged by exposure to light.
Given this information, I am very careful to keep my Fe supplement containers
out of the light.
I've done measurements using my LaMotte test kit and have had a difficult time
determining whether I am seeing a reading for Fe or just seeing the dust from
the powder on the bottom of the vial, so I'm not sure whether I'm measuring 0.1
ppm or not.
However, once I started adding the Dupla drops, my plants took on an immediate
color change. My H. polysperma is bright pink on top. My N. Stellata is a
nice mauve. My C. wendtii takes on a burnt orange with bright green highlights
on the tops of the leaves, while being red on the bottom. My R. indica is a
nice light red, and my alternathera, well it's alternathera.
Plants that don't seem to change color much are: H. difformis, A. nana, M.
pteroptus, V. spiralis, and A. crispus. The H. difformis gets red stems above
the water line though.
What does this mean? To me, it means I'm adding Fe to the tank in a manner
that is useful to the plants. OTOH, I'm not sure that I'm measuring it in the
water. I've backed down from 4 drops per day to 3 recently in my 55 to try and
help get a handle on my very successful red and blue algae (I added a phosphate
absorber to my tank temporarily to help with the blue, and I've cut my feeding
to 1/4 of what it previously was to try and reduce the red).
Anyways, I don't have a hair algae problem unless I go up to 5 drops/day, so I
guess I'm on the right track, even if I can't read the Fe levels using my test
David W. Webb
Enterprise Computing Provisioning
Texas Instruments Inc. Dallas, TX USA
(214) 575-3443 (voice) MSGID: DAWB
(214) 575-4853 (fax) Internet: dwebb at ti_com
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