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Re: Sera iron test



> Date: Fri, 27 Aug 1999 01:25:52 -0600 
> From: Michael Moncur <mgm at starlingtech_com> 
> Subject: Sera iron test 

>...  
> The Sera test definitely works with chelated iron, or at least it works  
> with whatever (DPTA, etc.) is in Tropica MasterGrow. If you give it 3-4  
> hours it works, but the response after 3 minutes is negligible.

This is interesting.  My Lamotte test simply would not find the iron in
Fe EDTA, given an hour or so to work.  It probably uses the same
chemistry as the Sera test, given the smell of sulfur, or rather sulfur
dioxide.

I'll have to try giving it multiple hours, but I don't have high hopes,
since it couldn't detect _10_ parts per million in the shorter
period.

Nobody ever told me, before I got in this list, that measuring Fe can be
useless unless you know what kind of chelation or complexing your
additive uses!  And it's still useless with the wrong additive.

IPOF I suspect that DPTA complex is easier to break than EDTA. And I've
found that ferrous gluconate is easily and accurately measured, with no
long wait required. This is an argument for using gluconate as the Fe
additive -- but we don't know how well that holds up in the aquarium.
(Do es it all xodize and precipitate quickly?)  I hope to have some kind
of answer to that question in a couple of weeks.
Experiment in progress.

-- 
Dan Drake
dd at dandrake_com
http://www.dandrake.com/