ICP Results Question on Zinc and Phosphates

[AndrewBrusca]

Hi All,

I hope everyone had a nice weekend! I have a question regarding ATI ICP test results I just received on my 225 gallon tank.

So everything looks pretty normal, except Zinc which came in at 22.48 UG/l.

The test says the ideal value is 2.02 UG/l. My previous ICP test from November 4th had Zinc as non detectable and my source water has always shown normal zinc.

My question, should I run a little Cuprisorb to lower zinc? For context, my Copper is at 3.33 UG/l. My tank seems to be doing fine, but I want to ensure my Acropora, and coral + fish generally aren't at risk.

Second question is, the ATI ICP test shows P04 Phosphate at 0.07 mg/l with an ideal value of 0.05 mg/l. Whereas my Hanna test kit consistently gives test results with a higher P04 phosphate range up around 0.12 - 0.16. Does everyone follow Hanna Phosphate results or ICP Phosphate results? My goal was to get my Hanna Phosphates down to around 0.07, and the discrepant ICP test is confusing me somewhat.

Thanks for any help,
Andrew

 

[Randy Holmes-Farley Verified Community Expert]

I would not assume that phosphate in a sample sitting around for multiple days will remain unchanged, unless special steps are taken to prevent microorganism growth.

Have you made any changes in your system that could possibly include a metal part in the water? Hose clamps, etc?

Was the last ICP the same type (ICP-OES or ICP-MS) as the current one?

 

[AndrewBrusca]

I would not assume that phosphate in a sample sitting around for multiple days will remain unchanged, unless special steps are taken to prevent microorganism growth.

Have you made any changes in your system that could possibly include a metal part in the water? Hose clamps, etc?

Was the last ICP the same type (ICP-OES or ICP-MS) as the current one?

Hey Randy, thanks for replying! I've done this ICP test three times now and it's been the ICP-OES test every time.

I'm happy to buy and run a bit of the Cuprisorb. But I think I saw another thread where a 20 UG Zing result was recommended against taking measures to lower it with Cuprisorb.

I don't have any new things added to the tank that would leak metals.. My RODI source water came back normal for zing. The only time metal has gone into the tank is when I briefly use frag/bone cutters with a new frag, but that doesn't seem significant.

In terms of your comment on the Phosphate sample sitting for multiple days. That indicates that you'd be more inclined to trust the Hannah test results right? I was planning on just sticking with the Hanna checker for Phosphates, so that makes sense

 

[Randy Holmes-Farley Verified Community Expert]

Hey Randy, thanks for replying! I've done this ICP test three times now and it's been the ICP-OES test every time.

I'm happy to buy and run a bit of the Cuprisorb. But I think I saw another thread where a 20 UG Zing result was recommended against taking measures to lower it with Cuprisorb.

I don't have any new things added to the tank that would leak metals.. My RODI source water came back normal for zing. The only time metal has gone into the tank is when I briefly use frag/bone cutters with a new frag, but that doesn't seem significant.

In terms of your comment on the Phosphate sample sitting for multiple days. That indicates that you'd be more inclined to trust the Hannah test results right? I was planning on just sticking with the Hanna checker for Phosphates, so that makes sense

I don't actually know which phosphate value is more likely accurate, and all are within my target range, so I personally would just keep on using the Hanna and act on it as you deem necessary.

I don't know if cuprisorb will be a net benefit or detriment since it will bind a bunch of things, but if you think the tank is visually doing fine, I'd hold off. If you think there is any sense of things worse than previously, or just not right, then I might use a metal binder.

 

[AndrewBrusca]

I don't actually know which phosphate value is more likely accurate, and all are within my target range, so I personally would just keep on using the Hanna and act on it as you deem necessary.

I don't know if cuprisorb will be a net benefit or detriment since it will bind a bunch of things, but if you think the tank is visually doing fine, I'd hold off. If you think there is any sense of things worse than previously, or just not right, then I might use a metal binder.

Makes sense. The only other source of zinc would be that I started dosing Tropic Marin Trace Elements (K+ and A-.)

However I'm only dosing 5 mgs per day on a 225 gallon tank. And since I started dosing tropic marin trace elements, it's brought a lot of major and minor elements to the target range so I don't think that's the cause of a zinc issue.

Okay so I won't go with a metal binder just yet as things look fine. I'll continue doing my weekly water changes, monitor the tank closely and run another ICP test in a couple weeks

 

[Randy Holmes-Farley Verified Community Expert]

Just double check that there are no float switches, clamps, algae scrapers, screws dropped in, etc. that might be corroding.

 

[AndrewBrusca]

Just double check that there are no float switches, clamps, algae scrapers, screws dropped in, etc. that might be corroding.

Okay great, that makes sense. I was banging around in the refugium and the sump recently.

So I'll double check every area of the tank. I'm pretty sure there isn't any metal corroding, but there aren't many other places it would come from so I'm looking. TY