Low sulphur levels is it an issue?

[Randy Holmes-Farley Verified Community Expert]

Sulfur in my aquarium is 740.1 mg/l.

Ati ref value against salinity (36,56 PSU) is at 976,2 mg/l.

That means I need to add 236,1 mg/l into my 2000 liter system.

The salinity is going to rise with this addition and is already pretty high, so correcting back to 35 ppt is going to have a depressive effect on other things.

Anhydrous sodium sulfate (the usual form sold) is 68% sulfate and 22.5% S by weight.

Thus, if you need 236 mg/L of S added per liter, you need 1.05 grams per L of Na2SO4 per liter.

In 2000 L, you will need 2.1 kg.

That addition will boost salinity by 1 ppt to 37.5 ppt. If you drop back to 35 ppt, everything (including S) will decline to 93% of its current or boosted value.

 

[Dimorb]

How much would you use to dilute this?

I tried to mix in 1 liter but it hardens and becomes solid..

Perhaps I need to use more.. 5 liters for example.. would there be any risk if I use an old nopox container?

 

[Randy Holmes-Farley Verified Community Expert]

How much would you use to dilute this?

I tried to mix in 1 liter but it hardens and becomes solid..

Perhaps I need to use more.. 5 liters for example.. would there be any risk if I use an old nopox container?

Wikipedia gives the solubility as about 280 g/L, so well more than 5 L RO/DI.

You also can consider slowly adding it directly to a sump or overflow as a dry powder, as long as you can ensure it isn't going to get to a delicate creature as an undissolved particle.

 

[Dimorb]

Wikipedia gives the solubility as about 280 g/L, so well more than 5 L RO/DI.

You also can consider slowly adding it directly to a sump or overflow as a dry powder, as long as you can ensure it isn't going to get to a delicate creature as an undissolved particle.

Thank you.

I started to mix before I had to go away and when I came back it was all hard. Like stone. Im trying to mix with a pump in a bucket to give it some temp at the same time.. have to wait and see how that goes.

When mixing 2.1 kg into 5 liters what do you recommend I should dose each day?

 

[Randy Holmes-Farley Verified Community Expert]

Thank you.

I started to mix before I had to go away and when I came back it was all hard. Like stone. Im trying to mix with a pump in a bucket to give it some temp at the same time.. have to wait and see how that goes.

When mixing 2.1 kg into 5 liters what do you recommend I should dose each day?

It won’t get that high at room temp. I’d add it over 5 days to limit the salinity jump.

 

[Dimorb]

Hello again and a big thank you for all your help.

This is what I've done so far.

Mixed 2,1 kg Sulphate from Triton together with 5 liters of RODI water. (Still cant find what's in the package from Triton, e-mailed them but no answer so far)

Connected a doser to dose sulphate solution as wanted and/or needed.

Connected another doser to remove water from the aquarium, to prevent large changes in salinity.

Last questions.

Q1. Is there a specific amount of water that should be removed in relation to how much solution is dose into the aquarium?

For example I'm planning to add the entire solution over a period of 14 days.

That will give a daily dose of approx 357 ml each day and divided into 24 hours it will result in a 14,9 ml dose each hour. I believe this will give me plenty of time to manage other parameters and total salinity, but should I remove the same amount of aquarium water - more - less?

By the way.. My salinity is 34,8 NOT 36,5 as the previous ICP shows. I've lowered it over a course of 2 weeks since I got the ICP results back.

Q2. Will this knowledge affect the calculations and amount of sulphate needed to raise sulfur 236 mg/l in my 2000 liter system or does it only affect the requested amount of sulfur in the system?

I dose balling and normally I remove some water at random, when relocating corals to others or skimmer removes some.. this keeps the salinity within my preferred range (34,8-35,2 PSU) -

Q3. Is there a relationship between what is dosed and the amount of water that should be taken out in total? For example if I dose 200 ml from each container should I remove 600 ml of water to even the salinity out?

@Lasse
@Randy Holmes-Farley

 

[Dimorb]

In addition to the previous post.

It seems I cant keep it dissolved. 2 kg mixed in 5 liters. Stays liquid in the container but "freeze" to crystal in tube.

If pressing the container on the sides I can hear it crackle so it's hardens in the container also.. only take more time.

When placed into a bucket together with a pump it stays dissolved. Why is that and what to do?

 

[Dimorb]

Wikipedia gives the solubility as about 280 g/L, so well more than 5 L RO/DI.

You also can consider slowly adding it directly to a sump or overflow as a dry powder, as long as you can ensure it isn't going to get to a delicate creature as an undissolved particle.

Terrible sorry.. didnt read good enough.
Need more RO water to mix.

Do you have any thougth on the other questions?

 

[Randy Holmes-Farley Verified Community Expert]

In addition to the previous post.

It seems I cant keep it dissolved. 2 kg mixed in 5 liters. Stays liquid in the container but "freeze" to crystal in tube.

If pressing the container on the sides I can hear it crackle so it's hardens in the container also.. only take more time.

When placed into a bucket together with a pump it stays dissolved. Why is that and what to do?

Yes, that's what I said. It takes more than 5 L. The pump may be warming the water a bit, increasing solubility

Here's a way to estimate water removal. If the salinity is 37 ppt and you want 35 ppt, you need to reduce the volume to 35/37 x 2000L and replace with RO/DI.

So it is removing 108 L. But 37 ppt is not exactly your situation. It's just an example.

 

[Randy Holmes-Farley Verified Community Expert]

The ratio of the solution you are adding to the solution you are removing will depend on the concentration in the solution you are adding.

Suppose you use 10 L total, so it is 2,100 g/10 L or 210 g/L. Seawater is about 35 g/L, so the dosed solution is 6x more potent and you'd remove 6x of tank water.

 

[Dimorb]

The ratio of the solution you are adding to the solution you are removing will depend on the concentration in the solution you are adding.

Suppose you use 10 L total, so it is 2,100 g/10 L or 210 g/L. Seawater is about 35 g/L, so the dosed solution is 6x more potent and you'd remove 6x of tank water.

Thank you again.

I've been using approx 25 liters to mix.. so it would be 2100 g/25 L = 84 g/l so the dosed solution is 2,4 times natural seawater.

I dose 48 x 15 ml each day. That's 720 ml.

If I understand you correctly I should remove 720 x 2,4 each day.. in total 1728 ml each day and replace with RODI water.. is that correct?

 

[Dimorb]

I'm not sure why my math doesnt add up.

I calculate it like this..

I mixed 2000 g powder of sulphate to add 235ish mg/l sulfur in a 2000 liters system into 25 liters RODI water.. 2000 g / 25 L = 80 g/L (in solution)

PSU at this moment measures 1,0228 g/cm3 equal to 1,0228 kg/l (according to GHL probe). That's the same as 34,4 PSU. (in the aquarium)

So 80 / 34,4 = 2,33

I dose 720 ml/day of the solution... I should remove 720 x 2,33 = 1674 ml/day (should I not?)

All in all since I started (22th dec) I've dosed 2737 ml of the sulphate/sulphur solution and removed 27626 ml seawater from the system. GHL probe went down from 1,0233 to 1,0228 kg/L but are stable last 24 hours.

Could this be correct? How? Is it possible my probe shows wrong value?

The calculations are only based on the addition of sulphate/sulfur solution and not the fact that I'm adding balling each day. I normally add kH (24x12 ml), CA (24x6 ml) NACL- (24x6 ml).

I use the following mix of balling:

Dunk 1
450 gram Kalciumkloriddihydrat, CaCl2 • 2H2O

Dunk 2
128 gram Natriumkarbonat, Na₂CO₃,
82 gram Natriumvätekarbonat, NaHCO₃

Dunk 3
128 gram Natriumkarbonat, Na₂CO₃,
82 gram Natriumvätekarbonat, NaHCO₃

Dunk 4
69 gram Magnesiumkloridhexahydrat, MgCl2. 6H2O
170 gram Natriumkloridfritt salt, NaCl FREE Salt.

 

[djkms]

Hello,

Can someone double check my math on this:

I have a 625 gallon system

I need to raise my Sulfate from 2343 to 2746

For sodium sulfate this will be 1,397grams

Based off this:
In order to raise sulphate by 1000 ppm and in the process raising sulfur with 333 ppm in 100 gallons of water one would need 555 grams of dry sodium sulfate.

I need to raise sulfate 403pppm (ideal 2746 per Oceamo)
555x.403=223.66x6.25=1,397grams

Curious what this will do to my salinity.

 

[korallen-koch]

Hey, I want to make a solution from Na2SO4 where adding 10 milliliter to 100 liter will raise S 10 milligram/liter. Is this calculation correct?

Na atomic weight: 22,99
S atomic weight: 32,06
O atomic weight: 15,999
Na2SO4 atomic weight: 142,04
32,06 x 100 / 142,04 = 22,6 wich means S proportion is 22,6 %

1 g Na2SO4 contains 0,226 gram S eq. 226 milligram S
1 g Na2SO4 added to 226 Liter will raise S 1 mg/l
0,44 g Na2SO4 added to 100 Liter will raise S 1 mg/l
4,4 g Na2SO4 added to 100 Liter will raise S 10 mg/l
So I dissolve 4,4 g Na2SO4 within 10 ml RO water to get the correct solution?

 

[Randy Holmes-Farley Verified Community Expert]

Hey, I want to make a solution from Na2SO4 where adding 10 milliliter to 100 liter will raise S 10 milligram/liter. Is this calculation correct?

Na atomic weight: 22,99
S atomic weight: 32,06
O atomic weight: 15,999
Na2SO4 atomic weight: 142,04
32,06 x 100 / 142,04 = 22,6 wich means S proportion is 22,6 %

1 g Na2SO4 contains 0,226 gram S eq. 226 milligram S
1 g Na2SO4 added to 226 Liter will raise S 1 mg/l
0,44 g Na2SO4 added to 100 Liter will raise S 1 mg/l
4,4 g Na2SO4 added to 100 Liter will raise S 10 mg/l
So I dissolve 4,4 g Na2SO4 within 10 ml RO water to get the correct solution?

The math looks good but you cannot make it that concentrated (and I see no reason to anyway). It is not that soluble.

 

[korallen-koch]

The math looks good but you cannot make it that concentrated (and I see no reason to anyway). It is not that soluble.

You're right. It's max 170 g/liter. Since I use a pelletreactor my tank needs a lot of sulphur. I bought a solution to raise sulphur. The label says 10 ml/100 l will raise "Schwefelgehalt" (=sulphur concentration "S") by 10 mg/l but the translation says it will raise sulfate ("SO4"). So maybe the labels is a little bit imprecise. I use a dosing system to keep sulphur in level and I wanted to have my own solution to be like the one I bought so I don't have to change my dosing rate. But I think I have to change my caculation to reference to sulfate and not sulphur. Thanks for the recommendation.

 

[Randy Holmes-Farley Verified Community Expert]

You're right. It's max 170 g/liter. Since I use a pelletreactor my tank needs a lot of sulphur. I bought a solution to raise sulphur. The label says 10 ml/100 l will raise "Schwefelgehalt" (=sulphur concentration "S") by 10 mg/l but the translation says it will raise sulfate ("SO4"). So maybe the labels is a little bit imprecise. I use a dosing system to keep sulphur in level and I wanted to have my own solution to be like the one I bought so I don't have to change my dosing rate. But I think I have to change my caculation to reference to sulfate and not sulphur. Thanks for the recommendation.

I'm not sure what a pellet reactor is or why anything in a reef tank would use up sulfate. Low sulfate usually comes from dosing calcium chloride.

Maybe we should explore that issue first.

That said, it probably means sulfate so requires much less.

 

[korallen-koch]

A pelletreactor can be used to lower NO3/PO4. It's filled with a biodegredable polymer. Bacterias consume the polymer under consumption of nitrates and phosphates. The bacterias and the assimilatet nutrients are then exported trough the skimmer. Since I use such a pelletreactor my sulphur dropped noticeable but I think I need to improve my knowledge on that calcium chloride thing because I also dose CaCl2. I use the faunamarin Balling light supply system for Ca, Mg an carbonate for ten years now. And since certainly five years I don't use the original components. Maybe they contain something that keeps sulphur in good level.

 

[Randy Holmes-Farley Verified Community Expert]

A pelletreactor can be used to lower NO3/PO4. It's filled with a biodegredable polymer. Bacterias consume the polymer under consumption of nitrates and phosphates. The bacterias and the assimilatet nutrients are then exported trough the skimmer. Since I use such a pelletreactor my sulphur dropped noticeable but I think I need to improve my knowledge on that calcium chloride thing because I also dose CaCl2. I use the faunamarin Balling light supply system for Ca, Mg an carbonate for ten years now. And since certainly five years I don't use the original components. Maybe they contain something that keeps sulphur in good level.

OK, you mean biopellets, which will not significantly impact sulfate at all. If you see a drop, it is for other reasons. Just like other organic carbon dosing, sulfate is mostly not impacted except in the most anaerobic environments.
Reducing sulfate significantly in any anaerobic environment is a big risk since hydrogen sulfide is a likely product.

 

[korallen-koch]

I don't think that there is an unusual anaerobic environment in my tank. It runs bare bottom with just a little bit sand in a glas bowl for the wrasse. I will check my icp and my documentation for the last 3 years.