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Re: Cu in Microplex

>Date: Wed, 02 Apr 1997 15:28:44 -0500 (EST)
>From: DIONIGI MALADORNO 201-812-3495 <DIONIGI.MALADORNO at roche_com>
>Subject: Cu in Microplex
> Miles Morrissey wrote: <<<<<< Subject: Cu in Microplex  (...) I noticed
>someone mention a few days ago about not using Microplex as a Trace Element
Mix because of the high level of Copper.  I am in the process of mixing PMDD
>but I'm now concerned that this copper will adversely affect the tank.  Will
>copper hurt my red ramshorn snails or malaysian trumpet snails??  What
>concentrations do I have to worry about?>>>>>>
>I am one of those who are a little bit concerned about the high copper
>content of Microplex (1.5%). This concern however is mainly due to the fact
>that I am specifically interested in keeping in my tanks water conditions
>compatible with invertebrates such as freshwater shrimps or mussels. If my
>calculations are right, using one tablesp. of Microplex in each 300 ml PMDD
>batch  would translate into a Cu concentration in the PMDD solution of
>0.45mg/ml and in the replacement aquarium water of 0.045 mg/l (with 1 ml
>PMDD/10 l relacement water). In aquaria books, acute exposure to Cu levels
>~ten times higher (0.5 mg/l) is known to have potentially toxic effects on
>fish and inverts, and I am not sure that a safety factor of 10 is adequate
>for chronic exposure.

I've been using Microplex in my PMDD for almost 4 months. I got an Aquarium
Pharmaceuticals Dry Tab Copper Test kit by mailorder mistake last year,
so I decided on checking my 90 gallon plant tank last night.

I measured the copper levels to be between 0.25 - 0.50 ppm.

Perhaps unrelated, but last September my tank was almost taken over by ramshorn
snails.  Now I have very few snails.  I thought that this was due to the snails
having a lot less algae to eat and also due to a calcium deficiency that I also
had a couple months back.


I mix two tablespoons (weight - mg???) of Microplex in a 300ml mix and dose at
about 7ml/day. I due 25% water changes every two weeks.

The copper test kit measures Cu2+ ions in increments of 0, 0.15, 0.25, 0.50,
1.0, 2.0, and 3.0 ppm

Does 0.25pmm Cu2+ =  Cu levels of 0.25ppm, or do I need to divide by some
conversion number?

>If my calculations are right, using one tablesp. of Microplex in each 300 ml PMDD<
>batch  would translate into a Cu concentration in the PMDD solution of 0.45mg/ml<

Please let me know if these calculations are correct.  If so, I'm in trouble.... :(

Two tablespoons of Microplex in each 300 ml PMDD => 0.90mg/ml of Cu in the PMDD.
So at 7ml/day, in two weeks I would have added 88.2mg (0.9*7*14) of copper
to my 90 gal (300 liters of waters) tank. The concentration of copper would
be about 0.3mg/l (88.2mg/300l) before the first water change.

Using the formula for ultimate concentration that I posted Nov. 18, 1996:

My copper levels using 25% Water change could be as high as 1.2mg/l!!!

(25% (r=3/4)  & (4 * X) => 1.2mg/l, where X = 0.3mg/l).  Assuming that the plant
don't use this metal, I would see this concentration after about 10 water changes
after I started adding PMDD - which is about a month from now.

Ron Wozniak  Allentown PA, USA
rjwozniak at lucent_com