Source for DIY salt mix ingredients?

[Wrench]

Does anyone know of a good source to acquire the ingredients for a DIY salt mix? Here is a list of the necessary ingredients.


For those who are interested, the following artificial seawater recipe is taken from "Chemical Oceanography" by Frank Millero. It makes a recipe that matches 35 ppt seawater in terms of major ions, but does not try to match all minor and trace elements, most of which will be present as impurities in the major elements.

23.98 g sodium chloride
5.029 g magnesium chloride
4.01 g sodium sulfate
1.14 g calcium chloride
0.699 g potassium chloride
0.172 g sodium bicarbonate
0.100 g potassium bromide
0.0254 g boric acid
0.0143 g strontium chloride
0.0029 g sodium fluoride
Water to 1 kg total weight.

[HighlandReefer]

You will need to buy the salts in large amounts (at least 50 lb bags in bulk) to begin to compete with the cost of salt mixes. You will need a place to store these in a protected area. You will need a mechanical method to properly mix these salts to properly combine them in large quantities. Trying to mix a small batch by hand is hard enough, much less larger batches. Thus, you will need to put out a considerable amount of money to initially do this.

It would be easier to buy a pallet (or several pallets) of salt mix and would be about as cheap or perhaps cheaper. Perhaps a group-buy at a local club would be better if you don't have the finances to invest in pallets of salt mix.

[Matt_Wandell]

Originally Posted by Wrench

Does anyone know of a good source to acquire the ingredients for a DIY salt mix? Here is a list of the necessary ingredients.


For those who are interested, the following artificial seawater recipe is taken from "Chemical Oceanography" by Frank Millero. It makes a recipe that matches 35 ppt seawater in terms of major ions, but does not try to match all minor and trace elements, most of which will be present as impurities in the major elements.

23.98 g sodium chloride
5.029 g magnesium chloride
4.01 g sodium sulfate
1.14 g calcium chloride
0.699 g potassium chloride
0.172 g sodium bicarbonate
0.100 g potassium bromide
0.0254 g boric acid
0.0143 g strontium chloride
0.0029 g sodium fluoride
Water to 1 kg total weight.

Before using that recipe I would calculate out the concentration added for each ion and compare it to NSW. You can find those numbers here:

http://www.mbari.org/chemsensor/pteo.htm

For simplicity, Atomic weight x Average concentration in ocean in mmol/kg = Concentration in mg/L

This is very important because in a salt like mag flake (magnesium chloride hexahydrate) over half of the weight is tied up as water molecules. If a recipe calls for a hexahydrate salt and you use an anhydrous salt you will have major problems.

I haven't looked at costs associated with every one of these salts but it's likely the sources for each ion can be tweaked as long as the final concentration remains the same. For instance there is no reason the sulfate needs to come from sodium sulfate, you can use magnesium sulfate instead.

I would skip the potassium bromide, there is plenty of bromide in calcium chloride as a contaminant now that Oxy-Chem doesn't remove it.

Here is one other recipe that will work, this mixes up to 35ppt for a little less than 20,000 gallons.

(a)=anhydrous

NaCl 4412lbs
MgSO4 (a) 632 lbs
MgCl2 (a) 368 lbs
CaCl2 (a) 196 lbs
KCl 124 lbs

NaHCO3 35 lbs

H3BO3 1875 grams
SrCl2 6H2O 1730 grams
KI 11.33 grams
ZnSO4 7H2O 5.23 grams
CoSO4 7H2O 3.92 grams
MnSO4 1H2O 2.30 grams
Na2MoO4 2H2O 2.16 grams
V2O5 0.43 grams

As far as sources, your biggest cost will come from the NaCl portion simply because of the proportion it contributes. You will want to find that as cheap as you can. Cargill and Morton are good places to start looking--get food grade without sodium ferrocyanate added.

The rest of the top 5 components can be found lots of places--try searching for salt distributors and pool supply companies in your state.

Cheapest place I've found sodium bicarbonate is at a rural feed supply store--apparently they use 50 pound bags to mix into cattle feed and you can get them for like $13. It's the same food grade stuff Arm & Hammer makes that we use in 2 part solutions.

The minor elements can be found cheaply at www.noahtech.com (big props to William Wing for finding this website).

Having said all that, after shipping and everything else I doubt it will be worth your trouble unless you are going through major amounts of salt. I would think if you can get a very large group buy together it might be worth the savings, but still, so much more work than just buying buckets of IO...

[Matt_Wandell]

Originally Posted by HighlandReefer

You will need a mechanical method to properly mix these salts to properly combine them in large quantities. Trying to mix a small batch by hand is hard enough, much less larger batches.

Well, mixing the dry salts together isn't completely necessary. If he makes very large batches of water, he can store and add the components separately each time.

For the minor components, we make up large batches of stock solution with a concentration such that, say, 100mL of solution will give us the required addition for each batch of salt water made.

[HighlandReefer]

Matt,

Thanks for the posts.

Do you guys measure the heavy metals in your final mix to see where they range?

Just wondering about the additions of zinc and cobalt:

ZnSO4 7H2O 5.23 grams
CoSO4 7H2O 3.92 grams

[rayjay]

After some help from Randy years ago, I used that recipe as the base for my present salt mix but I only use the base salts given at the top of that, and then mix my salt with Instant Ocean 50/50.
2400g sodium chloride (Sifto Crystal Plus water softener salt)(Walmart)
1350g magnesium chloride hexahydrate (not anhydrous)
400g sodium sulphate anhydrous
190g calcium chloride dihydrate (dowflake 77-80 or equivalent)
15g baking soda (I prefer to bake it 1 hr at 300F) or around 100ml of Randy's formula 1 alk portion.
When diluted to 1.026, produces about 33g of salt water but I only estimate this as I've never measured it.
As I'm in Canada, the location I buy from would not be of any use to you.
Unless you use a heck of a lot of salt water, it will probably be more expensive, or at least AS expensive as buying Instant Ocean as chemical companies now are requiring us to buy in large quantities or pay extreme pricing surcharges for smaller amounts.
I usually buy about 6-25K bags of the calcium and magnesium and 4-20k bags of the sodium sulphate, just to get pricing I can live with.

[Matt_Wandell]

Originally Posted by HighlandReefer

Matt,

Thanks for the posts.

Do you guys measure the heavy metals in your final mix to see where they range?

Just wondering about the additions of zinc and cobalt:

ZnSO4 7H2O 5.23 grams
CoSO4 7H2O 3.92 grams

Thanks!

Good question. I intend to do exactly that as soon as I work out some details with a university contact that has the fancy gizmos to test for it.

I have a hunch that both of those are probably present as impurities in the other components in more than enough abundance. But without testing it's hard to say that with any confidence.

We looked at it from a cost perspective and the addition of the minor elements (everything below KI) represent something like 0.5% of the total cost. So, it's not hurting our bottom line to add them. Whether or not it's necessary is a great problem to figure out.

[Matt_Wandell]

Originally Posted by rayjay

After some help from Randy years ago, I used that recipe as the base for my present salt mix but I only use the base salts given at the top of that, and then mix my salt with Instant Ocean 50/50.
2400g sodium chloride (Sifto Crystal Plus water softener salt)(Walmart)
1350g magnesium chloride hexahydrate (not anhydrous)
400g sodium sulphate anhydrous
190g calcium chloride dihydrate (dowflake 77-80 or equivalent)
15g baking soda (I prefer to bake it 1 hr at 300F) or around 100ml of Randy's formula 1 alk portion.
When diluted to 1.026, produces about 33g of salt water but I only estimate this as I've never measured it.
As I'm in Canada, the location I buy from would not be of any use to you.
Unless you use a heck of a lot of salt water, it will probably be more expensive, or at least AS expensive as buying Instant Ocean as chemical companies now are requiring us to buy in large quantities or pay extreme pricing surcharges for smaller amounts.
I usually buy about 6-25K bags of the calcium and magnesium and 4-20k bags of the sodium sulphate, just to get pricing I can live with.

Now there's an idea!

So you're not adding potassium at all? Have you ever tested for it? If I'm understanding your method correctly your K concentration would only be about half of what is in IO.

[rayjay]

No, I've not checked anything like potassium at all, just calcium and magnesium, but that was only years ago when I first started using this. Not since then though.

[UVvis]

Originally Posted by Matt_Wandell

Good question. I intend to do exactly that as soon as I work out some details with a university contact that has the fancy gizmos to test for it.

I have a hunch that both of those are probably present as impurities in the other components in more than enough abundance. But without testing it's hard to say that with any confidence.

As an analytical chemist, I have to say that the trace heavy metals in the seawater matrix are some of the hardest to analyze for.

For Wrench,

Factor in the labor and need for some good weighing equipment. When it gets hard to justify making your own blend from a cost savings perspective, you need to buy it in bulk.

For smaller systems where a water change is less than 5,000 or 6,000 gallons, get pallets of boxed/bagged commercial blends. I don't really trust super sacks to stay homogenous in transport/storage and prefer to only use the entire sack at once, be it 1,600 or 2,000lb sacks.

At work we do the math for salt additions by the ton. Even then, it is hard to justify the increased labor and personal risk of using individual salt blends. There are many salt blends out there, make sure their specs are what you want and get quotes. If you are buying enough you'll get competition for your busness.

[HighlandReefer]

UVvis,

Assuming you do run tests for heavy metals in your average salt mix batch, what does the copper level run at on average? If you have other heavy metal levels you can share like lead, zinc....etc, I would be curious as to their average levels as well.

If I had to guess, I would assume copper runs around 5-15 ppb.

[HighlandReefer]

Originally Posted by Matt_Wandell

Thanks!

Good question. I intend to do exactly that as soon as I work out some details with a university contact that has the fancy gizmos to test for it.

I have a hunch that both of those are probably present as impurities in the other components in more than enough abundance. But without testing it's hard to say that with any confidence.

We looked at it from a cost perspective and the addition of the minor elements (everything below KI) represent something like 0.5% of the total cost. So, it's not hurting our bottom line to add them. Whether or not it's necessary is a great problem to figure out.

I have done some preliminary searching in respect to the need for cobalt by coral and can't seem to find anything on it. If anyone knows of any use for cobalt by coral or other reef tank inhabitants, I would appreciate an explanation.

[Matt_Wandell]

Originally Posted by HighlandReefer

UVvis,

Assuming you do run tests for heavy metals in your average salt mix batch, what does the copper level run at on average? If you have other heavy metal levels you can share like lead, zinc....etc, I would be curious as to their average levels as well.

If I had to guess, I would assume copper runs around 5-15 ppb.

Shimek did an article for RK on exactly this subject. I think 10ppb was what he found for copper. For what it's worth the NSW values that Dr. Shimek lists in the article are way way off, by an order or two of magnitude in some cases.

[Matt_Wandell]

Originally Posted by HighlandReefer

I have done some preliminary searching in respect to the need for cobalt by coral and can't seem to find anything on it. If anyone knows of any use for cobalt by coral or other reef tank inhabitants, I would appreciate an explanation.

I seem to recall it is a coenzyme or used in B vitamins? I can't remember the exact biological role off hand, but there is a positive biological role for it. We probably add tons of it with food and impurities in the salt anyway.

[Allmost]

Hello all,
excellent info here thanks.

I read alot of older scientific papers, and most of them use the same formula for making the media in which they run their marine tests in

0.22 M NaCl,
0.026 M MgCl2,
0.01 M KCI,
0.005 M CaCl2,
and 0.1 mm FeSO4(NH4)2SO4.

something like this ....

now I have no Idea what that Iron sulfate .... FeSO4(NH4)2SO4 is, or where it can be bought from lol but does this look like a salt formula to you guys ? my chemistry background is too elementary to be able to say anything lol I just know which is methanol and which is ethanol :P haha

[UVvis]

Originally Posted by HighlandReefer

UVvis,

Assuming you do run tests for heavy metals in your average salt mix batch, what does the copper level run at on average? If you have other heavy metal levels you can share like lead, zinc....etc, I would be curious as to their average levels as well.

If I had to guess, I would assume copper runs around 5-15 ppb.

Don't really do it on salt batches. The problem usually is finding methods with low enough detection limits to get useful numbers for our full systems. It isn't abnormal for us to have under 2ppb copper in a system though.

Algae consume the copper pretty quickly from a system though. You have to watch your grazers for build up. This is one of those problematic aspects. Dietary heavy metals aren't in the water or freely available. So it's easy for some species to get build ups, especially with cultured microfauna.

Originally Posted by Matt_Wandell

Shimek did an article for RK on exactly this subject. I think 10ppb was what he found for copper. For what it's worth the NSW values that Dr. Shimek lists in the article are way way off, by an order or two of magnitude in some cases.

10 seems high to me. Copper usually doesn't make it's way into most of the processes for mining of purification of many of the salts used for sea water blends. I'll have to dig that up and take a look.

[Matt_Wandell]

Originally Posted by Allmost

Hello all,
excellent info here thanks.

I read alot of older scientific papers, and most of them use the same formula for making the media in which they run their marine tests in

0.22 M NaCl,
0.026 M MgCl2,
0.01 M KCI,
0.005 M CaCl2,
and 0.1 mm FeSO4(NH4)2SO4.

something like this ....

now I have no Idea what that Iron sulfate .... FeSO4(NH4)2SO4 is, or where it can be bought from lol but does this look like a salt formula to you guys ? my chemistry background is too elementary to be able to say anything lol I just know which is methanol and which is ethanol :P haha

That formula alone misses a lot of stuff, mostly sulfate or any sort of alkalinity. No carbonate/bicarbonate, no boron, and no strontium either. I would not stick animals in it.

I'm not familiar with that iron supplement. Randy Holmes Farley has written an article on iron dosing for AAOLM that has a good recipe using sodium citrate and ferrous sulfate to make ferrous citrate. The idea is that you want to complex the iron with an organic molecule so that it is slowly released. There are commercial versions of this for planted FW tanks, I think SeaChem makes a ferrous gluconate sol'n that works fine too.

[Matt_Wandell]

Originally Posted by UVvis

10 seems high to me. Copper usually doesn't make it's way into most of the processes for mining of purification of many of the salts used for sea water blends. I'll have to dig that up and take a look.

Yeah, it's just what he reported from reef tanks, not necessarily newly mixed salt. I can't say I recall any data from us testing it in our systems, or if we even have confidence in levels that low, so that is the only data I have. I seem to recall RHF reporting a similar number from his reef tank though.

(EDIT: Did just find one test we ran on our big reef tank--4 ppb copper. We haven't tested it since then.)

It's also possible that the bulk of it is coming in from certain types of food (macroalgae perhaps), and in smaller hobbyist sized systems it is building up to higher concentrations than you guys see it in your big exhibits, or you aren't feeding those types of food to begin with...(???)...all just guesses of course.

[UVvis]

Originally Posted by Allmost

Hello all,
excellent info here thanks.

I read alot of older scientific papers, and most of them use the same formula for making the media in which they run their marine tests in

0.22 M NaCl,
0.026 M MgCl2,
0.01 M KCI,
0.005 M CaCl2,
and 0.1 mm FeSO4(NH4)2SO4.

something like this ....

now I have no Idea what that Iron sulfate .... FeSO4(NH4)2SO4 is, or where it can be bought from lol but does this look like a salt formula to you guys ? my chemistry background is too elementary to be able to say anything lol I just know which is methanol and which is ethanol :P haha

That is an odd blend. Not much SO4. That looks more like a Marine Mammal/Sea Turtle blend that is made to be cheap and provide bouyance for the animals. Some of those types of systems are basically a chlorinated salt water swimming pool, so that really isn't a reef blend.

[Allmost]

Originally Posted by UVvis

That is an odd blend. Not much SO4. That looks more like a Marine Mammal/Sea Turtle blend that is made to be cheap and provide bouyance for the animals. Some of those types of systems are basically a chlorinated salt water swimming pool, so that really isn't a reef blend.

this is where I got this formula from ...

NUTRITION AND METABOLISM OF MARINE BACTERIA'
http://jb.asm.org/cgi/reprint/85/6/1413.pdf

have seen it in some other papers as well .. . I have no Idea if they just used that as a cheap alternative for these experiment or ....

[UVvis]

Originally Posted by Matt_Wandell

It's also possible that the bulk of it is coming in from certain types of food (macroalgae perhaps), and in smaller hobbyist sized systems it is building up to higher concentrations than you guys see it in your big exhibits, or you aren't feeding those types of food to begin with...(???)...all just guesses of course.

Some marine planktonic feeders like krill will sometimes have high copper counts, especially with the farm raised for fish food varieties. It varies lot to lot, so you can't really pin it down. Food and environmental additions like exposed corroded copper wire/pipe are more likely to contribute toxic heavy metals than from the salt blend.

[UVvis]

Originally Posted by Allmost

this is where I got this formula from ...

NUTRITION AND METABOLISM OF MARINE BACTERIA'
http://jb.asm.org/cgi/reprint/85/6/1413.pdf

have seen it in some other papers as well .. . I have no Idea if they just used that as a cheap alternative for these experiment or ....

Gotcha,

Quick scan without reading looks like they were more concerned with major cation balance than having a blend that mimics seawater.

[tanan]

Hey.
Since I have to pay about 120usd for a 200G instant ocean bucket here. I am looking into making my salt mix too.
I have access to sea salt (evaporated salt from sea water), should i use that and test/add for mag, cal and add trace? or should I test for more things?

[rayjay]

If you are trying to replicate a commercial salt or NSW, you wouldn't be able to test for many aspects of what you have unless you have access to a suitably equipped laboratory.
The mix I use (in post 6 above, worked out with Randy many years ago) was almost always used 50/50 with instant ocean salt. Occasionally for one of my fish only tanks I would use 100% of it but in a reef tank only 50/50.
To use a formulae 100%, I'd not do any less than Frank Millero's formula from which my formulae just uses the primary ingredients.
I'm not a chemist by any means but I do read often that sea salt will NOT redissolve into it's original mix, once by Randy, so it may not be suitable for your purposes unless you happen to know just what those changes might be and that they won't affect it's use for you.
While I've been using my formulae now for over 20 years, I have had to shut down all my reef tanks and FO tanks and now only have the seahorse tanks left, still using the 50/50 mix.

[bertoni]

The evaporated saltwater generally will have lost a lot of elements during the process. Precipitation and the like take their toll. The final product won't be appropriate for use here. The calcium and alkalinity will have combined to form sand, as well. I'll try to find a recipe for artificial saltwater, but it requires some specialty chemicals.