PMDD is based on the debunked belief that KNO3, PO4 and iron cause algae if dosed above the levels they recommend. Dosing recommendations on the
Krib link are extremely low but the information you will find there is important, most of it still holds up and the historical perspective is worth knowing. Just remember, low dosing levels were the doctrine of the time.
PMDD Pre-Mix is low on Potassium Nitrate, has no Mono Potassium Phosphate (PO4 and CSM+B do not mix w/out forming precipitates) and the Mg and Ca you need depends on what you already have in the water you put into your tank. They add magnesium sulfate to PMDD because in most cases water has enough calcium and tends to be low in magnesium.
EI is much more strait forward. Order the nutrients individually, KNO3, KH2PO4, CSM+B and GH booster if you need it to start with.
More info. about EI is found on this link,
http://www.barrreport.com/showthrea...Dosing-or-No-Need-for-Test-Kits?p=217#post217
I hope this helps.
