ICP test results --> very low sulfur

[Keiffer the reefer]

Many of the sps in my mixed reef have been eroding tissue lately. Some have been totally lost. All my standard params are measuring in good ranges so I sent a sample off to ICP-Analysis.com. Mostly, my results lead me to believe that water chemistry is pretty good. One notable item was my sulfur; it measured at 458 and recommends normal levels are ~1160. Less than half seawater levels! Reading a bit, it seems that magnesium sulfate (epsom salt) is probably a good source of sulfur I can use. My magnesium reading came in at 1230 so I think it's ok to add a bit. Little more reading tells me to not add more than 100ppm of Mg per day and that epsom increases S at 4 times the rate of Mg. I used the BRS calculator to figure out how much epsom salt to add to get 100ppm of Mg. So I think I've added 400ppm of S to my system. Tomorrow I'll send in another ICP test to see what really happened.

I'm curious to know if anybody else out there has experience such severely low S and if their tank was suffering. When reading Randy's articles about Sulfur cycle in the aquarium he indicates that Iron additions could be causing S to precipitate out. My tank is 52 gallons of total water and I dose 10mL of red sea color C/ day. I do this because my only nutrient export is macro algae in my refugium; no skimmer. Interestingly, ICP results say iron is 0.

Another interesting thing I noticed was that immediately after adding the epsom salt, my ORP reading immediately starting climbing. Usually, ORP declines during the day and rises at night. I added the epsom about 2.5 hrs before lights out and it caused ORP to change from declining to rising.

 

[Shaddow_wolf169]

Never tested it but someone will jump on I'm sure.

 

[Randy Holmes-Farley]

The only way sulfate can get low is for the salt mix to be low (unlikely if it is a decent brand) or for you to supplement calcium for a long time with just calcium chloride (chloride rises and sulfate falls over time). Test error is also a possibility.

At 35 ppt (sg = 1.0264), sulfur should be about 900 ppm as sulfate. I cannot imagine why they claim 1160 ppm and YOU SHOULD NOT TARGET 1150 ppm.

Iron is typically very low, and even ICP won't detect normal levels.

The ORP change from adding Epsom salt is probably due to metallic impurities in it, such as ferric iron.

 

[Cory]

Id be really interested to know if your corals come back to life from your sulphur correction!

What kind of salt?

 

[JimWelsh]

If you want to supplement sulfate without adding magnesium, or want to add more sulfate than is possible with reasonable magnesium sulfate additions, you can always use sodium sulfate. https://www.dudadiesel.com/choose_item.php?id=1ssf

 

[jason2459]

I'm curious what brand saltmix you are using?

 

[mazoli]

The only way sulfate can get low is for the salt mix to be low (unlikely if it is a decent brand) or for you to supplement calcium for a long time with just calcium chloride (chloride rises and sulfate falls over time). Test error is also a possibility.

...

The ORP change from adding Epsom salt is probably due to metallic impurities in it, such as ferric iron.

Got in a very similar situation few months ago. I went with no waterchanges for about a year, then did an ICP test, got the same result: sulfur was low. Started dosing MgSO4 to raise it. After a few weeks my acroporas started loosing tissue, and a black, powderlike film started showing up on everythin, brown turflike algae growing on rocks. 2 of my urchins died. I figured it is because of metallic impurities from the mgso4, but was not sure what. A second ICP test did not reveal any "known" trace elements to be high, so still have no idea what impurities might have caused it.

And now I'm reading about Randy's comment about ferric iron. Yes, this is what might have happened in my case as well. I was doing fine with low sulphur, I just wanted to make it even "better". Then lost about half of my acros with STN over about 2 months (once they start, they won't stop).

Watch out for impurities, buy the best quality possible!

 

[Hans-Werner]

Never trust any test result blindly, neither test kits nor electronic devices nor laboratories. Allways do changes slowly, controlled and watch the corals and other invertebrates very carefully and critically.
Maybe impurities where the cause for losses maybe it was the sudden change of conditions that evolved very slowly before. Even improvements can be fatal if they are done too fast.

 

[mazoli]

Never trust any test result blindly, neither test kits nor electronic devices nor laboratories. Allways do changes slowly, controlled and watch the corals and other invertebrates very carefully and critically.
Maybe impurities where the cause for losses maybe it was the sudden change of conditions that evolved very slowly before. Even improvements can be fatal if they are done too fast.

Yes, completely agree with what you say. Lesson learned.

 

[Keiffer the reefer]

I sent in another sample three weeks ago and I'm just now getting around to posting. I also tested a fresh batch of my salt mix, Tropic Marin ProReef. I have lost all but three of my acros. I have not really seen any visible change in the health of my tank through all of my testing/dosing experiment. All other tank inhabitants are healthy (lps, softies, montis, birdsnest). Appears to just be some kind of acropora issue.
Here is image of the original test:

After getting these test results back, I added 100ppm of Mag via Epsom salt. That was clearly a mistake based off the next batch of results. I also added some strontium and some potassium. Here is the next batch of results:

Sulfur went through the roof. I clearly had some major miscalculation in the ratio of sulfur to Magnesium. Or, the test is not accurate; I suspect it to be some combination of both. Fortunately, there doesn't appear to be any negative affects on the animals. My mag calculation was spot on. My strontium dose ended up way short of expected outcome. I'll continue to dose small amounts and watch closely, however, Randy's articles indicate I probably shouldn't even worry with this element. Potassium dose worked out the way I intended; I plan to start monitoring this element and might set up on small automated doses. Phosphorus did spike a little; I wonder if the sulfur spike affected the algae in my fuge. Macro algae is my only nutrient export system. Either way, I'm not really worried about the level from this reading.

Here is the readings from Tropic Marin ReefPro. For the most part it looks good to me. However, there were a few interesting things I've noticed. Bromine is 86ppm (similar readings in my display), but there is no info on levels in seawater. Seems like there's a lot in there for something that doesn't have a sea level average. Potassium is a little high. This is interesting to me because my display is low despite my water changes adding it back in. Seems like I might have a much higher K uptake than I thought. Phosphorus seems kinda high for a salt mix to have. But, I don't really know jack about all the salt mixes. Its not a level that's really concerning to me. Strontium is a little higher than my display which makes me think my tank's consumption is more than I originally thought.

 

[Randy Holmes-Farley]

There are some serious errors here.

Epsom salt adds 1.3 times as much sulfur as magnesium. The huge increase can't be accurate. Maybe none of the S values are.

 

[Randy Holmes-Farley]

The bromine is not a concern. It is fairly abundant in seawater (67 mg/L) and many mixes have more than NSW levels.

What is Seawater? by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2005-11/rhf/index.php

 

[Randy Holmes-Farley]

What company ran these tests? They do not inspire confidence.

 

[Keiffer the reefer]

ICP-Analysis.com

 

[David S]

If you want to supplement sulfate without adding magnesium, or want to add more sulfate than is possible with reasonable magnesium sulfate additions, you can always use sodium sulfate. https://www.dudadiesel.com/choose_item.php?id=1ssf

Hi Jim
I just received my ICP result from ICP-ANALYSIS.
Results we're pretty good, with the exception of Sulfur which was 689 PPM. They recommend 800-950 PPM.
It's true that I dose Calcium Chloride, but it is to supplement kalkwasser dosing.
Currently my CA is 457 PPM and MG - which I also dose - is 1398 PPM.
First, do you think the low S is a concern?
Second, if raising my S is desirable, would lowering my Calcium Chloride dosing so that CA is lowered to 400 - 420 Ppm raise my S to an acceptable level.
Thirdly, if dosing NA2SO4 IS the way to go, how do I determine how much to dose?
Thanks
David

 

[JimWelsh]

Hi Jim
I just received my ICP result from ICP-ANALYSIS.
Results we're pretty good, with the exception of Sulfur which was 689 PPM. They recommend 800-950 PPM.
It's true that I dose Calcium Chloride, but it is to supplement kalkwasser dosing.
Currently my CA is 457 PPM and MG - which I also dose - is 1398 PPM.
First, do you think the low S is a concern?
Second, if raising my S is desirable, would lowering my Calcium Chloride dosing so that CA is lowered to 400 - 420 Ppm raise my S to an acceptable level.
Thirdly, if dosing NA2SO4 IS the way to go, how do I determine how much to dose?
Thanks
David

I doubt it is much of a concern. I'd get a second opinion from another testing service first. If you decide to make an adjustment, I would not adjust your Ca in order to adjust S. Yes, adding Na2SO4 is a good way to adjust S. Na2SO4 is 22.5% S, so in order to raise 100 gallons of water by 100 mg/L (PPM) S, it would require 0.100 (g S) / 0.225 (% S) * 3.7854 (L/gal) * 100 (gallons) = 168.24 grams of Na2SO4.

 

[David S]

I doubt it is much of a concern. I'd get a second opinion from another testing service first. If you decide to make an adjustment, I would not adjust your Ca in order to adjust S. Yes, adding Na2SO4 is a good way to adjust S. Na2SO4 is 22.5% S, so in order to raise 100 gallons of water by 100 mg/L (PPM) S, it would require 0.100 (g S) / 0.225 (% S) * 3.7854 (L/gal) * 100 (gallons) = 168.24 grams of Na2SO4.

Thanks Jim
I'll do a Triton test at year end before I do any tinkering.
If I do find that dosing is necessary, could I mix the NA2S04 into my fresh saltwater?

 

[JimWelsh]

If I do find that dosing is necessary, could I mix the NA2S04 into my fresh saltwater?

You should be able to. Depending on the Ca level of your ASW and the amount of Na2SO4 you add, you might see some white CaSO4 precipitate, but it should redissolve once fully mixed with your tank water. Ideally, though, you would mix the Na2SO4 with fresh water and use it as top off water or something like that.

 

[David S]

You should be able to. Depending on the Ca level of your ASW and the amount of Na2SO4 you add, you might see some white CaSO4 precipitate, but it should redissolve once fully mixed with your tank water. Ideally, though, you would mix the Na2SO4 with fresh water and use it as top off water or something like that.

I dose my Kalk as top off so I guess I would mix it with my Fritz salt ( the non or less enhanced version ).
If low S is confirmed I would start off conservatively anyway.
I'll let you know how things turn out.
Thanks again

 

[David S]

I dose my Kalk as top off so I guess I would mix it with my Fritz salt ( the non or less enhanced version ).
If low S is confirmed I would start off conservatively anyway.
I'll let you know how things turn out.
Thanks again

Jim
I just received results from another ICP company. This one is affiliated with Fauna Marin.
Sulphur in the tank measured to 749 PPM.
This is a bit higher - but probably not significantly higher - from the previous test.
My takeaway is, my tank is slightly deficient in S.
Fauna Marin recommends 800 - 900 PPM while ICP.ANALYSIS recommends 800 - 950.
I plan to add a small amount of Sodium Sulphate to my makeup water.
Can it be added to Kalkwasser?