PMDD Dosing Schedule

["Kinney, Travis" <kinney at pdtarchs_com>]

Kirk M.,
 Over a year ago I started the planted aquarium thing using the PMDD. I
bought my ingredients from the same source as you. I would encourage you to
stop mixing the PMDD formula and also purchase some K2PO4 (monopotassium
phosphate). The PMDD formula is based upon the Sears and Colin study on PO4
limited fertilization. What you may find with the PMDD mix is that it does
not meet the needs of your tank. I found dosing with PMDD and measuring for
Fe pushed me into dosing way too much ferts into my tank. I have since
switched to dry dosing individual ingredients and testing for NO3 and PO4 as
well as regularly testing Ph and KH for determining CO2 levels. I find the
dry dosing easier and can raise or lower individual ingredients depending on
what's happening in the tank. For example, after a water test I might find
that nitrate levels are just fine, but phosphate is undetected. By dosing
dry ingredients, I can increase the PO4 dosing and keep NO3 the same. With
the pre-mixed PMDD you don't have that option, and invite trouble by getting
ferts unbalanced.

I rarely test ferts, maybe once a month if that. I do about 30% water change
a week. I take a small cup filled with hot water upstairs to where my ferts
are kept, and place a pinch or so of whatever I'm dosing into the water. By
the time I go back downstairs to my tank, the ferts are dissolved and I dump
it into the tank. There are times that I notice the perling increasing
within an our of dosing, but most often it is kept on an even keel of things
running balanced.

Print a copy of this and keep it handy til you get things memorized.
http://www.sfbaaps.com/reference/barr_02_02.shtml

-Travis