RE: Aquatic Plants Digest V5 #18

["Newsletter " <Newsletter at brazeltonhotels_com>]

Thank you to Scott Heiber and Paul Sears for helping me better
understand the impact of a UV Sterilizer.

Scott wrote:

>>Ultra Violet will break down at least some chelators, such as EDTA,
which >>can affect the levels of available iron -- 

Paul Sears wrote:

>> 	The point was that the UV steriliser seemed to be rendering
>> micronutrients unavailable.  When it was turned _off_, Kevin was able
>> to cut the dose of "PMDD" without running short of trace elements,
>> and the reduction of dose caused the potassium shortage.

My understanding is that my UV Sterilizer probably is speeding the
breakdown of chelators that bind the micronutrients (such as FE - iron)
resulting in a higher dosage of PMDD being required (consistent with the
original Sears-Conlin study).

Along time ago, Kevin Conlin wrote:

> The new formula is 1tbsp trace element mix, 1tbsp epsom salts, 2tbsp 
> KNO3, and 2tbsp K2SO4.  My original formula was developed while I was 
> using a UV sterilizer.  When I turned off the sterilizer, I needed 
> much less PMDD to maintain my iron levels, and the plants ran short of

> macronutrients, primarily K.

Thus, my interpretation is that when Kevin turned off the UV sterilizer,
he did not need to dose as many trace elements due to possible breakdown
of chealtors (thus reducing the total dosage of PMDD).  This reduction
in the total PMDD dosage reduced the KNO3 that was being added resulting
is a shortage of potassium (K).

The increase in KNO3 from 1tblsp to 2tbsp is due to the reduced dosage
of PMDD and thus the need to increase potassium (K).

*IF* I got this right; then thanks to Mr. Paul Sears and Scott Heiber, I
have a little better understanding.

Greg aka Newsletter.

P.S.  I think it was Karen Randall who once wrote that no matter how
clear you might be in a lecture, some novice is likely to leave grabbing
ahold of one piece of information that when taken in isolation (or out
of context) can be quite wrong.

All of the discussions about PMDD are tied to testing for Iron levels
(in retrospect, that is pretty clear) ... yet to me, PMDD was a means to
achieve Nitrate ... proof of the dangers of giving a novice a little
information <GRIN>!!!!!! Ms. Randall was once again proved right!
<G>!!!!

... the other reminder that finally clicked for me, is that the PMDD
recipe and dosage is guide, not a rule ...