Disappearing Copper

Tom Barr

Staff member
Jan 23, 2005
Most test kits test total copper, they should say if they only test free copper.
I'm doubtful that a copper test kit will yield useful results at lower ranges unless it's done right after dosing. Plant uptake also is an issue for any dosing, vs what gets targeted for algae or precipitated out of solution etc.

And like NO3/PO4 test kits, a reference standard is a nice thing you could use to check, all for more $ , time and labor(what?You do not wanna do that? :p ).

I think I'd not bother with copper unless you used an EI style dosign and knew the tap was fairly well Cu free. So a large 80% followed by dosing a known solution to say 0.2ppm. Wait a day or two, then a large water change, then perhaps another 2 days after. Adding a full Excel dose would also help each time + a trim and + CO2 adjustment, and continued Excel dosing thereafter+more water changes till the algae goes away.

Hit it with several things, not just one if you want it gone sooner rather than later.
You can always avoid test kits dosing know amounts into aquariums and doing a large water change thereafter, or use carbon to remove left overs, and scrub clean, then dose again etc.

Left over copper being resuspended is possible, but unless you are doign a lot of copper dosing for BBA over time, not too likely.

Tom Barr

Tom Barr


Lifetime Charter Member
Lifetime Member
Jun 21, 2009
Surprise, AZ
guy tillmans;42821 said:
Do plants need cupper? What do we do when we use 100% RO water whit GH and KH addition? (assuming that there is no cuper in RO water). Is there any/enough cupper in csm-b?

Yes, plants need some copper. http://www.barrreport.com/barr-report-newsletter/1963-barr-report-newsletter-copper-zinc.html is a good read on copper and its role in the transport of nutrients

Most micronutrient products include some copper.

Plantex CSM+B is, I believe, 0.09% copper, I think the standard dose is likely non-limiting for copper. I dose at least 10 times the standard dose, so I am likely not the best person to answer, the limiting, non-limiting part.

Edit: Wrote the above from memory (dangerous) found websites listing the copper in Plantex CSM+B ranging from 0.007% to 1.5%.

Checked a bag of Plantex CSM+B from Planted Aquarium Fertilizer - Home and it lists the guaranteed anaylisis as 0.10% copper (cu) (chelated).

Sorry, for any confusion.

Detritus Mulm

Guru Class Expert
Jun 12, 2005
Copper is holding, although I'm not quite sure where. I'm having trouble interpretting the shades of blue. It's definitely darker than .1, but not Purple like .25. It's likely somewhere around .2, but .5 looks more Blue than Purple to me, so it's a little hard to tell. The fish are telling me it's likely .2ish.