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post #4 of (permalink) Old 04-25-2013, 05:11 AM
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Join Date: Dec 2003
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I tend to dose 15 ppm 2x a week of KNO3. Rarely 3x.

This seems good enough for most every plant species I've ever encountered, which is perhaps 400 species or so at this point.

If you look at a basic uptake and nutrient concentration graph:

EI targets the D range. A rich sediment like ADA AS, at least for the 1st few months, MTS etc, will do this as well.

By good observation, you can target the C range and slowly reduce and watch the plant's response.

Older methods used PO4 limitation to produce A and B ranges, which caused greatly reduced growth and also, less CO2 demand because plants were far more limited by PO4 or some other nutrient than CO2. Thus when they added the PO4 or the limiting nutrient, they then would have CO2 limitation, which tends to lead to algae, thus a myth is born.

Hair algae seems more due to CO2 than anything else or plants growing and blocking the current. GHA tends to be near the current areas on the plants that block the current or are in the path of the current. This is also true in streams and rivers.

Also, do not assume the CO2 is 39 ppm, it might not be since the KH might be less than you think it really is. While we like to think it's all bicarb, sometimes it is not depending on the tap water.

Algae and plant health are better test kits, if not the best test kits. I'd focu there, provide ample nutrient, then mess with the CO2 mostly, and then good horti/aquaculture from there.

Tom Barr
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