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PMDD has too much iron

Andrew Claxton has algae problems when following the "suggested" dosage
for PMDD.

I think this subject has come up before. The original and "latest"
recipes for PMDD have too much chelated iron in them to be used at the
"suggested" dosages. Actually you're SUPPOSED to adjust the trace
nutrient level to achieve 0.1 ppm Fe. Given that many iron test kits do
not seem to be able to accurately measure 0.1 ppm Fe, many people have
had to learn to decrease the amount of trace nutrients they use or to
dose them separately.

Also, I have found that the density of the latest chelated trace
elements (weight per tablespoon) has DOUBLED from the earliest samples
that I have so when you use the tablespoon approach, you may be getting
more than was originally expected.

Here is an alternative which will supply much LESS iron but which may be

Dissolve 1 tbsp (10 grams) of chelated trace elements in 3 cups (750ml)
of water. Add 1 tsp (5ml) of this solution with each 10 gallons (40L) of
water changed. CTE is 7% iron.

Here's the concentration I work out:

10 g x 1000mg/g x 7% x 5/750 / 40L = 0.12 mg/L

Using this dosing method, you should never exceed 0.1 ppm of iron in
your water (assuming none coming from the substrate). Try this for a
while; I bet its enough to keep your plants very happy and avoid
encouraging the algae!

Steve Pushak                              teban at powersonic_bc.ca 

Visit "Steve's Aquatic Page"      http://home.infinet.net/teban/
 for LOTS of pics, tips and links for aquatic gardening!!!