copper test interference?

salty joe

Active member
I plan on using Randy's recipe for iron, (Thank you Randy!) because I'll be using an algae scrubber.

"solution containing 5 g of iron (as 25 g of ferrous sulfate heptahydrate) in 250 mL of water containing 50.7 g of sodium citrate dehydrate" from here http://www.reefkeeping.com/issues/2004-05/rhf/index.htm

After dissolving in water, I want to test each chemical individually for copper. Do you think I can get a good idea if these chemicals are copper free using Salifert?
 
It doesn't really test test low enough for reef safe levels of free copper ( around >30ppb). I'm not aware of a hobby kit that can. It's fine for establishing a therapuetic level for treating fish disease but invertebrates are much more senmsitive to free copper than fish.
 
I didn't realize copper was toxic at such low levels. But if this test can be trusted, I have less than 50ppb. (0.05 ppm would show a faint blue according to Salifert) At least you could tell if a certain chemical was badly contaminated with Salifert.

I used hydraulic cement and Portland cement mixed with play sand and latex paint and thought any one of those could be contaminated with copper.

After looking at a picture of ferrous sulfate, my guess is it will not be a clear liquid when dissolved in water, making the Salifert copper test useless. If that's the case, I'll get lab grade and hope for the best.
 
I don't know much about impurities in the cement or play sand. Aluminum might be an issue with hydraulic cement perhaps alkainity. Someone else may chime in with more detail.
 
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