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RE: PMDD problem

> Date: Mon, 13 Oct 1997 17:06:48 -0400
> From: Martyn Mitchell <kathmart at istar_ca>
> Subject: PMDD problem
> Hi from Canada:
> I am having great difficulties obtaining appropriate iron
> concentrations using PMDD. I'm using the Sears recipe and dosing
> recommendations as found in the Krib .
> The water here is absolutely brutal so I'm forced to use 100% RO for
> changes.
> I am using a Sera test kit. When adding PMDD at recommended dosage to
> 100L RO during water changes my test kit registers zero ppm iron.
> I then did a test adding PMDD to 1 litre of RO. It took the addition of
> approx. 1 ml PMDD to read between 0 and .25mg/L iron content.
> This means that I would have to add 100 ml PMDD to my 100 L of change
> water? Can this possibly be right?

I had a similar problem.  Eventually I determined that the Sera iron test 
kit works very poorly.  Next I bought the Red Sea kit, which would show 
iron when it was present, but I eventually found it reading 1 ppm iron even 
when none was present (as confirmed by testing pure RO/DI water).

Recommendations on the net seem to be for Hach and LaMotte kits, both of 
which are more expensive than what you will likely find in the local pet 
shop.  I got a LaMotte kit and have been very happy with it.  (BTW: Refills 
are not terribly expensive.  The original kit is because of the *very* nice 
"Axial Reader" that comes with it.)

Good luck!

The very act of seeking sets something in motion to meet us;
something in the universe, or in the unconscious responds as if
to an invitation.  - Jean Shinoda Bolen