High zinc and it won't go away

[Leon821019218]

I'm confused. I've set up my new tank about 4 months or so. After the cycle I slowly added some corals that I kept from my old tank. A few leathers and 4 hammers (small ones). I noticed that fairly soon the heads started to shrink and die one by one. Leathers are doing good. At first I thought it was because the tank and everything was new but did an ATI icp test (7-22-25) and it showed pretty high zinc levels 34.86 µg/l. There was also Zinc in my RO/DI water. I figured that I was putting more zinc into the tank every time I did a water change and via the ATO. So i changed all the filters, membrane and even the booster pump. After that I did a lot of water changes. And added cuprisorb to the tank. Few weeks later i send in another icp test (8-9-25) assuming the levels would be a lot lower. Well, I got the results in yesterday in the are even worse at 48.59 µg/l! There in no zinc in the RO/DI this time, so that's a good thing... The equipment is not showing any signs of corrosion, no metal clips or anything in the tank. The sand is all new. The scape/rockwork is all new. I'm using reef crystals. Anyone got any idea where to look or what to do because I don't know. Been reading a lot of topics on the internet but I'm not finding the solution. Zinc is a tricky one I guess...

 

[Lavey29]

Elevated zinc is typically caused by eroding equipment somewhere.

 

[Leon821019218]

Yeah I know. Checked everything. My return pump (sicce voyager) is brand new. The heater is brand new. Only 'old' gear is a AI nero 5, Maxspect gyre, jecod sow flow pump and Tunze flow pump. Those I disassembled and cleaned before using them again in the new tank. From what I could see, no signs of corrosion. I use a polyethyleen tub to mix in the water. Which from what I read so far, can't leech zinc into the water.

 

[Lavey29]

Yeah I know. Checked everything. My return pump (sicce voyager) is brand new. The heater is brand new. Only 'old' gear is a AI nero 5, Maxspect gyre, jecod sow flow pump and Tunze flow pump. Those I disassembled and cleaned before using them again in the new tank. From what I could see, no signs of corrosion. I use a polyethyleen tub to mix in the water. Which from what I read so far, can't leech zinc into the water.

On a side note, I dose zinc weekly for color in my acros. Elevated zinc at your levels is probably not harmful but it would be nice to find the source. Have you checked your heater magnets or anything that is on a magnet probe?

 

[Lavey29]

From Fauna Marin:


A too high zinc value is mostly caused by the input via fish feed.

 

[Leon821019218]

On a side note, I dose zinc weekly for color in my acros. Elevated zinc at your levels is probably not harmful but it would be nice to find the source. Have you checked your heater magnets or anything that is on a magnet probe?

According to ATI zinc values above 10 are harmful. I have over 40 which is way to high. I know that a little bit of zinc is necessary for healthy corals but what I have is not. My hammers are dying because of it. Heater is in very good condition, it's a brand new Eheim. Checked the magnets from the flow pumps again just now and they all look good!

 

[Leon821019218]

From Fauna Marin:


A too high zinc value is mostly caused by the input via fish feed.

I feed 2 cubes of frozen food daily at max and some flakes/pellets. My tank is almost 600L, do you think that could be the culprit??

 

[Lavey29]

I feed 2 cubes of frozen food daily at max and some flakes/pellets. My tank is almost 600L, do you think that could be the culprit??

Well i would research it a bit and find out if you are certain no equipment is at fault. I feed frozen twice daily and occasionally a pellet snack.

 

[Lavey29]

According to ATI zinc values above 10 are harmful. I have over 40 which is way to high. I know that a little bit of zinc is necessary for healthy corals but what I have is not. My hammers are dying because of it. Heater is in very good condition, it's a brand new Eheim. Checked the magnets from the flow pumps again just now and they all look good!

Do you have magnet for your ATO sensor?

Can you post complete parameters including par numbers

 

[Leon821019218]

Do you have magnet for your ATO sensor?

Can you post complete parameters including par numbers

Didn't check that one. Did it just now and it's also looking ok!. Don't have the PAR numbers but I don't see how that is relevant to zinc levels? Oh btw, The PO4 was higher the last test but I think it's so low now because of all the water changes.

 

[Lavey29]

Well you have multiple areas there that are critical to coral health that are way off. Zinc would be a distant secondary concern to me. You have no iron, no phosphate, somewhat low nitrates for LPS , no detectable manganese, etc...

Do you dose trace elements? Or do weekly water changes?

 

[Leon821019218]

Normally weekly water changes. Nitrates and Po4 were higher like I said but I did water changes like crazy to get rid of the zinc. Didn't dose yet because of the low number of corals in the tank and thought that the elements in the new saltwater were sufficient for the low number of corals I have. This was the test I did before

 

[Lavey29]

Normally weekly water changes. Nitrates and Po4 were higher like I said but I did water changes like crazy to get rid of the zinc. Didn't dose yet because of the low number of corals in the tank and thought that the elements in the new saltwater were sufficient for the low number of corals I have. This was the test I did before

Ok that one looks better. Read up on the food you are using to see if any zinc connection. Do you defrost your frozen in cup of tank water and strain it before adding to the tank?

 

[Randy Holmes-Farley Verified Community Expert]

No hose clamps anywhere in or near the water?

 

[Boehmtown]

I think I remember someone suspecting their black ato bucket. I think it was zinc

 

[Leon821019218]

Ok that one looks better. Read up on the food you are using to see if any zinc connection. Do you defrost your frozen in cup of tank water and strain it before adding to the tank?

Will check up on that tomorrow! Time for me to hit the rack. It's almost 1 am in the night over here ;)

No hose clamps anywhere in or near the water?

If I need to clamp like a hose to a pump or something I use those big Tie wraps.

 

[rishma]

Wonder if it’s in your freshly mixed saltwater instead of contamination of the tank. Check for metal parts after RODI associated with mixing new salt.

ICP is not cheap but I’d consider checking freshly mixed water if all else fails.

 

[Randy Holmes-Farley Verified Community Expert]

Zinc is used in some plastics, so that source is a possibility, though I would not expect it to readily be released to the water.

 

[Reginald Reefer III]

Zinc is used in some plastics, so that source is a possibility, though I would not expect it to readily be released to the water.

Polo Reef had an episode awhile back where they had extremely high zinc and they traced it back to Brute trash cans they were using for a GFO contraption they made. Removed the brutes and the zinc went away.

 

[Randy Holmes-Farley Verified Community Expert]

Polo Reef had an episode awhile back where they had extremely high zinc and they traced it back to Brute trash cans they were using for a GFO contraption they made. Removed the brutes and the zinc went away.

I use more Brutes than almost anyone (at the time of my icp, my total system used 11 x 44 gallon grey Brute cans) and did not have elevated zinc when tested, but it may have already been gone by then.