Seachem Copper test results

[Spar]

I just started doing Cupramine for my first time. I am confident that my tank + sump holds 90 gallons of water combined. I put in, over 4 days, the respective amount of Cupramine to get to .50ppm, but when testing it now it looks closer to .35-.40 in the color test, to my eyes anyway, but it is so hard to tell for sure.

Should I trust the Cupramine dosing amount that I am at .50ppm, or should I trust my eyesight and put more in?

 

[Spar]

As I was typing the post I thought about using the .5ppm reference solution that comes with it. Here is a side-by-side comparison (left is from my tank, right is the .5 solution):

TANK WATER:

.5ppm SOLUTION:

How could it be that off?

 

[MrTuskfish]

Copper tests are hard to read. I'm lucky to have a kid and a helper who seem to just have the right "eye" for this stuff. Any rock or substrate in the tank? They can absorb Cu and remove it from the water column. Cupramine at .35 is perfectly acceptable, its the dose I've used for years and SeaChem says its a high enough dose too. Its easier on the fish as well; most fish can handle Cu up to about .80; but I see no reason to go higher than .35-.40. Taking several days, if the fish aren't in real trouble, helps fhttp://www.seachem.com/Products/product_pages/Cupramine.htmlish adjust to the Cu too. Here's some good info on Cu; the FAQ are really important.

 

[Spar]

Bare tank with just a heater, powerhead and PVC T's, so nothing that should be absorbing it.

In the pictures I posted above, it really doesn't even look like I am at .3ppm even. I don't think I halved the dosage, but almost appears that way. I put in a total of 17.2ml of Cupramine over the course of 4 days. To my calculations that is the right amount for 90g's volume water. (2ml per 10.5gallons). I used a Salifert 1ml syringe to get to that @ 4.3ml per day.