Zinc and copper - help please

[ajm83]

I have some problems with my reef (STN, RTN, no pods, high invert mortality) so I had a Triton ICP test done 3 months ago.

High copper (29 µg/l should be 0.1 )
high zinc (62 µg/l should be 4)
high silicon (1040 µg/l - should be 100)
high aluminium (109 µg/l - should be 2)

All the rest were okay.

So I added cuprisorb and found a rusting magnet in my tunze 9004 skimmer. This was removed and all other equipment thoroughly checked (nothing else visibly corroded). No screws in there, no rusted covers etc.

3 months on, things are slightly better, I now have visible pods. However coral is still looking awful and I randomly get stripping, and any new coral deteriorates after a week or two.

So I get another ICP test and get the following results:

High copper (9.321 µg/l - improvement of 20 ug/l but still far too high compared to NSW)
High zinc (75 µg/l, 20% increase!)
high silicon (1715 µg/l, 65% increase!)
high aluminium (90 µg/l, 20 µg/l reduction)


So what's going on?!

Salt: red sea blue bucket
Water: RO/DI with 0 TDS.

Potions dosed: Sodium carbonate anhydrous (spec is here: https://apcpure.com/product/sodium_carbonate_anhydrous_99_3)

Food: mix of various frozen (quality brands) and Prime reef flakes


So how do I remove the remaining copper and zinc? And what is the source of my silicon?

Is there any chance these things can be coming from my RODI even though it registers 0 TDS and I regularly change the DI?

Help, I'm losing the plot!! I have read so much on this and usually the end result is somebody pulling out a big old rusty chunk of metal. But I have a small tank and there is nowhere else to look!

Are there any alternative ways to remove metals? Macro growth?

I stupidly already bought triton's detox (£27/100 ml), then emailed them and they said it doesn't help with zinc ;Dead

 

[Randy Holmes-Farley]

I'd replace the cuprisorb. I had 13-15 ug/L copper without apparent issue, but removing more is a good plan.

Neither the silicon nor aluminum are killing corals, but i'd try to keep aluminum moving down.

No, 0 ppm TDS RO/DI is not likely a source.

The zinc is likely still a problem. A polyfilter might be a good choice to add.

Any metal parts above the water corroding?

 

[ajm83]

Thank you Randy. I'll replace that cuprisorb.

Nothing above the tank corroding.

I mentioned the prime reef flakes having seen they were relatively high in zinc on one of you're articles. Is that likely to be a significant contributor do you think?

Would macro algae take up these metals?

 

[ajm83]

Also I found this article in my web trawl:
http://www.advancedaquarist.com/2012/2/chemistry

Looks like GFO would hit the copper, zinc and silica in one go!

So is using GFO a good approach? I have minimal phosphate so I'd most likely need to feed extra or maybe dose a little potassium phosphate which I have knocking about from my planted F/W tank to avoid stripping the tank bare.

 

[Randy Holmes-Farley]

FWIW, I'd be VERY careful interpreting that data to suggest that GFO will remove the types of copper present in typical reef aquaria at the concentrations usually found.

Free ionic copper (that test) quickly gets bound to organics in seawater (such as in the ocean) and will have very different binding properties. But so much was added to that test that i expect most stays ionic since there is not all that much organic around.

That said, it is possible that GFO may bind some copper. So will GAC (because it binds the organics that are holding the copper).

 

[Randy Holmes-Farley]

I doubt any food has enough zinc in it to drive the values way up unless there's some sort of problem in its manufacture.

 

[ajm83]

Thanks again, I'm not *AS* worried about copper to tell the truth as I have Cuprimine which seems to be able to remove that, but seemingly no way to remove zinc so that's why it jumped out at me (plus the silicate of course).

 

[Randy Holmes-Farley]

The silicate will be removed by GFO, but is no concern unless you have a diatom problem.

I'm similarly concerned about interpreting the zinc data.

Such experiments really need to be done at concentrations present in the real case, and your actual starting level is much lower than the lowest level attained in that experiment after the GFO..

 

[ajm83]

No, 0 ppm TDS RO/DI is not likely a source.

The zinc is likely still a problem.

Hi, I'm still struggling with this. The levels dropped for a while and everything looked better but took a turn for the worse in the last two weeks and an acro stripped. So I had an ATI ICP test done which checks the RODI water as well as the tank.

Results as follows:

TANK
zinc: 90 ug/l
copper: 7 ug/l

RODI
zinc: 4.4 ug/l
copper: 1 .7 ug/l

I have replaced all the equipment now in the tank, heaters, powerheads, skimmer, lights, ATO system.

I guess the RODI is the prime suspect. It still shows 0 TDS (got a new TDS meter also!) I guess 4.4 & 1.7 ug/l are too low to show up on the TDS meter but enough to accumulate through top-off water etc.

Does this just imply I need another DI stage on my RODI system?

Thanks!

 

[2una]

Rodi - cu + zn - any brass fittings on it?
Silicate - siporax perhaps?
Aluminium - marine pure blocks?

 

[ajm83]

Rodi - cu + zn - any brass fittings on it?
Silicate - siporax perhaps?
Aluminium - marine pure blocks?

Hi mate, see my post above yours, I think it's coming through the rodi somehow. I've just ordered a 3 stage resin chamber to increase the time spent in the resin. Will see if that improves things

 

[2una]

Hi mate, see my post above yours, I think it's coming through the rodi somehow. I've just ordered a 3 stage resin chamber to increase the time spent in the resin. Will see if that improves things

Understand it might be coming from behind it, but there's no brass fittings been used on the RO unit, like on the booster pump if your using one?. I also have copper that seems to keep appearing & i'm now wondering whether maybe the brass in my atu solenoids is where its coming from as i can't find any other source.

 

[ajm83]

Understand it might be coming from behind it, but there's no brass fittings been used on the RO unit, like on the booster pump if your using one?. I also have copper that seems to keep appearing & i'm now wondering whether maybe the brass in my atu solenoids is where its coming from as i can't find any other source.

I'm lucky With my water pressure so I don't need to use a booster, and I think the to unit is all plastic inside. Guessing the water pipes are copper though. Not sure on the zinc source


On your setup, brass sounds like a definite possibility

 

[Randy Holmes-Farley]

Hi, I'm still struggling with this. The levels dropped for a while and everything looked better but took a turn for the worse in the last two weeks and an acro stripped. So I had an ATI ICP test done which checks the RODI water as well as the tank.

Results as follows:

TANK
zinc: 90 ug/l
copper: 7 ug/l

RODI
zinc: 4.4 ug/l
copper: 1 .7 ug/l

I have replaced all the equipment now in the tank, heaters, powerheads, skimmer, lights, ATO system.

I guess the RODI is the prime suspect. It still shows 0 TDS (got a new TDS meter also!) I guess 4.4 & 1.7 ug/l are too low to show up on the TDS meter but enough to accumulate through top-off water etc.

Does this just imply I need another DI stage on my RODI system?

Thanks!

I have generally not been a fan of ATI's testing of RO/DI water because it comes with no guidance and may make people act in ways that are not productive.

IF the copper really was 1.7 ug/L in your RO/DI, then I would be concerned. In that case, getting a second DI and putting it in series would be a good plan.

BUT, Triton posts their uncertainty data, and they, at least, would not be able to accurately measure that amount of copper in seawater. It is too low. They say their limit of detection is 1.2-3.5 ppb.

https://www.triton-lab.de/fileadmin/user_upload/triton-lab/TRITON_LOD.pdf

I have no idea what ATI's limit of accurate quantitation is on an RO/DI sample, but I would allow for the possibility that it is just testing noise.

 

[ajm83]

I have generally not been a fan of ATI's testing of RO/DI water because it comes with no guidance and may make people act in ways that are not productive.

IF the copper really was 1.7 ug/L in your RO/DI, then I would be concerned. In that case, getting a second DI and putting it in series would be a good plan.

BUT, Triton posts their uncertainty data, and they, at least, would not be able to accurately measure that amount of copper in seawater. It is too low. They say their limit of detection is 1.2-3.5 ppb.

https://www.triton-lab.de/fileadmin/user_upload/triton-lab/TRITON_LOD.pdf

I have no idea what ATI's limit of accurate quantitation is on an RO/DI sample, but I would allow for the possibility that it is just testing noise.

Many thanks, I have ordered the extra DI chambers, so I'll update the post next time I get an ICP test done.

 

[Randy Holmes-Farley]

Many thanks, I have ordered the extra DI chambers, so I'll update the post next time I get an ICP test done.

Sounds good.

Good luck!

 

[2una]

BUT, Triton posts their uncertainty data, and they, at least, would not be able to accurately measure that amount of copper in seawater. It is too low. They say their limit of detection is 1.2-3.5 ppb.

https://www.triton-lab.de/fileadmin/user_upload/triton-lab/TRITON_LOD.pdf

I have no idea what ATI's limit of accurate quantitation is on an RO/DI sample, but I would allow for the possibility that it is just testing noise.

I came across it the other day Randy , this here yes?
http://atiaquaristik.com/en/?page_id=1422

 

[Randy Holmes-Farley]

I came across it the other day Randy , this here yes?
http://atiaquaristik.com/en/?page_id=1422

yes, thanks!

Based on that data, the copper level may well be real and a second DI resin is a good plan, assuming it came through the resin and not from some other sources, such as the storage containers, drips of condensation from pipes over the container (one lady had that), a screw at the container bottom, etc.

 

[ajm83]

yes, thanks!

Based on that data, the copper level may well be real and a second DI resin is a good plan, assuming it came through the resin and not from some other sources, such as the storage containers, drips of condensation from pipes over the container (one lady had that), a screw at the container bottom, etc.

The water from the RO/DI unit goes straight into a HDPE water butt, made from recycled materials (not through the pictured 'filler kit'). Can't find anything online to say that material is a likely source of metals. I did however find this: https://www.ncbi.nlm.nih.gov/pubmed/17258284 which seems to be specifically about zinc from white HDPE (though my water butt is green). Also there is no mention of copper.

There is no metal piping or anything similar near by, and the water butt's lid is sealed tight, then I have a silicone cover over the whole thing. Fairly confident nothing is getting in. I took the RO water sample from the water butt, so the metals are not coming from ATO pump (which I already replaced anyway with a brand new, quality pump, just in case - it's eheim or tunze or something).

Thanks for linking that data @2una, very useful.

Anyway the extra DI units have arrived just now, so I will dump the stored water and get on with doing water changes, then after payday I will send another ATI ICP test off.

 

[Randy Holmes-Farley]

The water from the RO/DI unit goes straight into a HDPE water butt, made from recycled materials (not through the pictured 'filler kit'). Can't find anything online to say that material is a likely source of metals. I did however find this: https://www.ncbi.nlm.nih.gov/pubmed/17258284 which seems to be specifically about zinc from white HDPE (though my water butt is green). Also there is no mention of copper.

There is no metal piping or anything similar near by, and the water butt's lid is sealed tight, then I have a silicone cover over the whole thing. Fairly confident nothing is getting in. I took the RO water sample from the water butt, so the metals are not coming from ATO pump (which I already replaced anyway with a brand new, quality pump, just in case - it's eheim or tunze or something).

Thanks for linking that data @2una, very useful.

Anyway the extra DI units have arrived just now, so I will dump the stored water and get on with doing water changes, then after payday I will send another ATI ICP test off.

Thanks for posting the link. That's interesting about the jugs.

Let us know how things progress!