Low sulphur levels is it an issue?

Randy Holmes-Farley · Dec 21, 2016

You need to raise sulfur (S) by that amount, right, not sulfate (SO4--). Sulfate needs a much bigger rise since you count the weight of the oxygen atoms on it. Sodium sulfate is 67.6% sulfate by weight (make certain it is sodium sulfate (Na2SO4) and not sodium bisulfate (NaHSO4), which will wipe out your alkalinity).

Sulfate weighs 3 times as much as sulfur, so a 377 ppm rise in sulfur means a 1129 ppm rise in sulfate.

1129 mg/L * 0.676 = 1,670 mg/L sodium sulfate needed, or 1.67 g/L.

Note that will boost salinity a LOT! From 35 ppt to 36.7 ppt.

Mortie31 · Dec 21, 2016

Thank you Randy

Mortie31 · Dec 21, 2016

Wow thats 1336 grams!!! ill have to wait until after Xmas now...

Randy Holmes-Farley · Dec 21, 2016

Mortie31 said:
Wow thats 1336 grams!!! ill have to wait until after Xmas now...

5 pounds of food grade sodium sulfate only costs $13. Now that I see that availability, it may be worth developing a more complete DIY 2 part recipe (no third part).

http://www.ebay.com/itm/like/231263306651?lpid=82&chn=ps&ul_noapp=true

Mortie31 · Dec 22, 2016

Yeah it does seem to be readily available, I've orderd some and some magnesium sulphate to add to my dosing, maybe I'll just dose the sodium sulphate as I don't get much af a mg drop, trouble is how much and how often, if you worked it into your dosing formula that would be great.. hint.. hint. Thanks again for your help chaps

Randy Holmes-Farley · Dec 22, 2016

You're welcome.

Happy Reefing.

Ehsan@triton · Dec 22, 2016

Hi All ...
And thank you Randy for drawing my attention to this problem. Much appreciated.
Sorry to all readers for that missunderstandable mail, but our support agents which we choose very conscientious are not all chemists or scientists, so a lot of detail in that answer is missing which makes it very missunderstandable.
https://www.dict.cc/englisch-deutsch/conscientious.html
Sulfate (SO4) is not at all dangerous itself, it is one of the four main "substances" of seawater. ( Big Four ) .
But before dosing it is important to understand why the SO4 is missing in the aquarium.

As SO4 is normaly not consumed by our animals like Ca or Mg there will be other reasons for it to "disapear".
One of the most common reasons is, it has never been there ;-) means you had too less of it in your saltmix used.

The other one ( less often ) could be a degassing out of the aquarium as bacteria could change the form of SO4 to a gas leaving the tank trough the surface or the skimmer.
The changover is often happening in anearobic areas of the aquarium ( Bacteria could cause visible colored patches ), like a deep sand bed or a freshwater external filter ( still used by some aquarists ).
Some of these gases can be quite dangerous and have a strong smell, and we experienced in the past that some aquarists have problems because of this.

There is no problem to use Na2SO4 in the first case, as you just add what the saltproducer missed to mix in the salt.
But there is a need of being carefull in the second case as you would add SO4 and give the existing bacteria the possibility to create more gas.

TRITON is about knowing what you do and finding the cause of a problem, not only about treating symptomes ... in this case the syptome is the missing SO4.

Again sorry for the misleading answer we all do our best to get aquarists more successfull.

To all of you a merry Christmas and all the best for the new year.

Randy Holmes-Farley · Dec 22, 2016

Thanks, Ehsan.

A third reason is folks supplementing calcium with calcium chloride only. I think that is probably the most common one for most folks.

Cory · Dec 22, 2016

Randy Holmes-Farley said:
Thanks, Ehsan.

A third reason is folks supplementing calcium with calcium chloride only. I think that is probably the most common one for most folks.

Wouldnt sulphur be low compared to chloride, but not lower than natural seawater in this case? Like high chloride normal sulphur.

Randy Holmes-Farley · Dec 23, 2016

Cory said:
Wouldnt sulphur be low compared to chloride, but not lower than natural seawater in this case? Like high chloride normal sulphur.

If you maintain salinity, sulfate must drop in that scenario. The effect can be quite strong even with small additions if water changes are not correcting it.

I show here that adding 8 ppm of calcium and 1.1 dKH of alkalinity every day leads to a sulfate drop from 2710 ppm to 2170 over a year, or a drop of 20%.

http://reefkeeping.com/issues/2006-02/rhf/index.php

Cory · Dec 23, 2016

Randy Holmes-Farley said:
If you maintain salinity, sulfate must drop in that scenario. The effect can be quite strong even with small additions if water changes are not correcting it.

I show here that adding 8 ppm of calcium and 1.1 dKH of alkalinity every day leads to a sulfate drop from 2710 ppm to 2170 over a year, or a drop of 20%.

http://reefkeeping.com/issues/2006-02/rhf/index.php

I see. But that effect only applies if your dosing magnesium sulphate to maintain magnesium right?

Randy Holmes-Farley · Dec 23, 2016

Cory said:
I see. But that effect only applies if your dosing magnesium sulphate to maintain magnesium right?

The effect to lower sulfate comes from the calcium chloride additions. The solution to that particular problem can be to use magnesium sulfate for most of the magnesium dosing.

Mortie31 · Dec 23, 2016

What's really strange is the Balling lite and indeed classic balling systems don't mention this sulphate drop at all, I have been using balling lite for 4 years, only recently adding a kalkstirrer. Their recipes are to dose CaCl and Mgcl, so probably explains why over this time my sulphur ended up low, they did advise using MgSuplphate years ago but stopped giving that advice, I wonder how many users are in the same position I currently find myself in, I would of never known without a triton test... Saying that my reef looks fine so not sure it's an issue, but it may of become one... who knows..

Cory · Dec 23, 2016

Randy Holmes-Farley said:
The effect to lower sulfate comes from the calcium chloride additions. The solution to that particular problem can be to use magnesium sulfate for most of the magnesium dosing.

Sorry Randy im lost lol. Its not your fault. But i really want to understand the reason for a drop in sulphur from CaCl. This is what im thinking:

Calcium chloride is both calcium and chloride. So it raises both calcium and chloride, but lowers nothing. If it lowers sulphate, is it by precipitation or something? For example if i have 20,000ppm chloride and 900ppm of sulphur, a CaCl addition would raise the Cl part by 1, making it 20,001ppm chloride (as an example). While the sulphur wouldnt lower or raise at all because no sulphur is added or removed. (That i think)

Where is the error in my thought?

So in that case chloride should rise but sulphur stays the same unless its being reduced by something? Its my understanding nothing is really using sulphur.

Or am I misunderstanding you?

Sorry for interupting this thread

jason2459 · Dec 23, 2016

I'm also curious, to those with low sulfur results do you happen to also use an Aquaforest saltmix?

Mortie31 · Dec 23, 2016

jason2459 said:
I'm also curious, to those with low sulfur results do you happen to also use an Aquaforest saltmix?

I have used both AF probiotic and more recently AF reef salts, but switched to dosing their NaCL free salt about 3 months ago and I have reduced water changes since then, but having checked my last 3 triton tests since June sulphur levels and they have all been low.

Randy Holmes-Farley · Dec 23, 2016

If you dose calcium chloride, you dose both calcium and chloride.

You must also be dosing sodium carbonate or bicarbonate (or else there is no demand for calcium). So you are dosing sodium and carbonate.

Corals use up the calcium and the chloride and leave behind sodium and chloride.

The residual sodium and chloride cause salinity to rise. Maybe 10-10o% over the course of a year.

Of course, people are correcting for salinity changes by maintaining salinity at a target value. So effectively that means replacing some tank water with RO/DI (although it can be done with lower than tank salinity changes, loses due to skimming, etc.).

When the salinity is adjusted downward, everything drops. Sodium and chloride were already boosted so they drop back toward normal. Of the big 4, that leaves magnesium and sulfate to drop. People maintain magnesium when needed, so that leaves sulfate to drop and never be corrected.

Hence, sulfate declines over time.

Mortie31 · Dec 29, 2016

Just mixed 1000g of Na2SO4 in 10L of RODI water I'm planning on dosing 500ml/day, over next 20 days, I'm basing this on the reply I got from triton and Randy's calculation in an earlier post but I have mixed a weaker solution as I can't find any info on dosing it at all, if anyone thinks I'm wrong please shout out soon.. or indeed if I can dose more per day. I will also keep an eye on salinity as Randy advised..

jason2459 · Dec 29, 2016

Mortie31 said:
I have used both AF probiotic and more recently AF reef salts, but switched to dosing their NaCL free salt about 3 months ago and I have reduced water changes since then, but having checked my last 3 triton tests since June sulphur levels and they have all been low.

Interesting. I asked as the Aquaforest salts I had tested by Triton and them showed low Sulfur.