Doug, generally 2-3x a the recommened amount is a common range for
folks with CO2/good light.

I'd add 7mls 3x a week.

Don't bother testing.
Search for testing for iron on this and other forums, it's a rather in
depth issue and iron water cheosirty is complicatd to say the last and
the test kits do not tell what you need to related to plant health.

The eye ball works better than a test kit here.
Keep everything else in good shape: CO2/GH/NO3/K/PO4 then plpay with
this variable.

Adding X amount per tank volume so many times a week yields the best
results, give 3-4 weeks before trying another dosage etc.

I've done this in the past, TMG, Flourish, Sera etc all are pretty
close.
At max light, 6w/gal, the max uptake/needed for good growth was 5 mls
dosed 3x a week. Few folks will go beyond this light value. Excess
does not harm at lower light.

Test kits vary considerably, but volume in mls x frequency x tank size
is a stable parameter and is constant.

Regards,
Tom Barr






Doug wrote in message ...
Hey all!

Quick question: How much iron/potassium supplement do you add to your
planted tanks?

I've got a youngish, planted (about 16 species) 30-gal with 80 watts
(400 Lux) broad-spectrum fluorescent lighting, DIY CO2, and a light to
moderate fauna load with a latterite enriched substrate. This tank is
just starting to really take off and I'm finding it hard to keep the
iron concentration up. I'm having to add up to between 10 and 15 mL per
day of (pick your favorite iron/potasium supplement) Leaf Zone (0-0-3),
which instructs 5mL per 10gal once a week. Just curious how hungry some
of your well planted tanks are. Perhaps I've got something that just
eats it up, like my Hygrophilia corymbosa or perhaps Ceratophyllum
demersum or Aponogeton crispus?

Anyway, what is the consumption on your tanks?

-Doug