pmdd question HELP!!!

dean9922

Junior Poster
Apr 26, 2009
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hi there...just recieved my dry ferts and have several questions....
what i recieved was the following:
K2S04
MGS04
KN03
CSM+B trace

my first question is if you follow the Conlin & Sears formula they say to add 1tbsp of trace, 1 tbsp of MGS04, 2 tbsp of K2S04 and 1 tbsp of KNO3 mixed into 500 ml of distilled water and recommended dosing of for each 10 gallons add 1/12 ml. to start with and measure and monitor the Fe level and the NO3 level. Does this sound correct. If so, it makes life easy as I have a 30, 76 and 100 gallon tanks and calculating proper amounts is easier.
I've been on fert calculators and it's so confusing and some seem to contradict each other with amounts to use.
secondly, if this is "not" a good recipe for pmdd does anyone know of a simple one to follow within reason, as i do realize you have to monitor your levels.
thirdly, can you mix all ingredients together or should you do them seperately.

any help would be appreciated as i am starting to get confused......i should also mention i am not running CO2 but definitely need some ferts as i am getting black algae on the leaves of my plants, so they must be missing some nutrient.
 

Philosophos

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Mar 12, 2009
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At first glance I'd say KH2PO4 is missing. I don't use CSM+B so I can't recall what it's PO4 level is. Might want to check that.

-Philosophos
 

VaughnH

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Jan 24, 2005
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Sacramento, CA
PMDD is obsolete! It was formulated back when phosphates were believed to be something to remove from the water, not add to it. If you want to use that system, at least add KH2PO4 seperately - there is no phosphate to speak of in CSM+B. I suggest that you just follow the EI method of dosing instead.
 

Tom Barr

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Jan 23, 2005
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The addition of nutrients like PMDD suggest is fine if you add PO4, the notion that adding a nutrient solution that limits PO4 is not founded(has been falsified).

So if you modify the PMDD to include PO4, then it's a useful method.
However, why it works, is not/cannot be correct.

If it where, then all tanks adding PO4 should have algae, but that's not the case.


Regards,
Tom Barr