Reef Salt expire ?

[Antman]

Hello all I bought some salt 1/2 price at a store that was closing . They did not do high volume and the salt sat for a while . It was clumped up in the bag I broke it up as much as I could but still clumpy . It is not mixing well over night with power head and heated water . Is this normal does it go bad .

[mcgyvr]

Yes it can go bad and it being hard/clumpy is a sign of that...it may still be acceptable though it could just be off in regards to elemental values..
For fish only it wont really matter...coral tanks may be potentially problematic

[LIreefguy]

You could try testing alk,cal, mag
If they are the same as manufacturers suggested I would say the salt is ok. If they are way off I would probably throw it away


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[bosshog]

How can salt go bad? It’s anhydrous and will take on moisture and clump, but degrade? Anyone have anything to back that up, I’m curious.

[LIreefguy]

It doesn’t go bad as in spoil.
The elements in the salt will bind with each other making the saltwater it produces different than intended




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[bosshog]

Originally Posted by LIreefguy

It doesn’t go bad as in spoil.
The elements in the salt will bind with each other making the saltwater it produces different than intended




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? How does that happen in a bucket, but not in the tank?

[LIreefguy]

it does happen In tank. Precipitation by heaters and pumps

Plus it also will happen in tanks if you dose alk and calcium in the same spot at the same time

It has to do with the Concentration of salt being a lot higher that your tank


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[billdogg]

When salt clumps like yours has, the part that won’t dissolve is calcium carbonate that has precipitated out of the mix. It is very much usable, but if it’s for a reef with stony corals you will need to test it for calcium, alkalinity, and magnesium and bring them back in range. If it’s a fish only or soft coral tank it will be fine.

HTH!

[herostar]

I made a big order a couple years ago that took almost 2 years to get through. I definitely noticed a difference in my coral health and overall tank health when I got a brand new bucket after the big order was completely used up. I never tested the water toward the end of the old batch, though (shame...).

[gogo7]

salt doesnt expire.
if your tank is mature with mature corals growing in it..ie over 3 years ...i wouldnt be worried about the 'expiry date' of your salt.... and even then..
if youre using additives and testing anyways who cares? its salt.
if youre changing water regularely?.then dont worry too much about what your corals are sucking out of the column... youve got bigger things to deal with. you're all over the testing and youve already paid for additives... so why care about 'expiry' date of salt.
if your tank is under 3 years old i wouldnt worry too much about the chemistry.
youll drive yourself nuts and spend money on things you dont need.
make sure the salinity isnt too high or too low. change water when it looks crytal clear.
the animals have sucked all the nutrient from the column and are looking for more.
dont let your filtration suck all those out

[Uncle99]

If you keep corals, Always deploy fresh salt.
While salt itself does not expire, it does absorb elements from its surroundings.
Why take that risk?

[HumbleFish]

I wouldn't hesitate to use it for a fish only, but maybe test the Big 3 (alkalinity, calcium, magnesium) before dumping the water in a reef. You can always dose baking soda, calcium chloride, or even magnesium chloride to the mix if necessary.

[dkeller_nc]

OK, folks, a little chemistry to clear things up. Billdogg has it correct, I'm just going to expound on his explanation a little.

Unless the salt mix contains organics (there's a few brands that do, but not very many), it can't "spoil" as in go rancid or grow bacteria.

The principal element in a salt mix is, of course, sodium chloride. The principal minor elements are calcium chloride, sodium bicarbonate and/or sodium carbonate, magnesium chloride and sodium or magnesium sulfate.
That's 99%+ of the salt mix. There are many other ionic salts in the mixture, but they are all present in minute quantities, so we can ignore them for this discussion.

As most know, calcium carbonate is insoluble for all practical purposes in pure water. Among other potential reactions, calcium carbonate can be formed by mixing ionic calcium with an ionic carbonate. For our purposes, the principal source of these two reactants is calcium chloride and sodium carbonate/bicarbonate.

To actually get calcium chloride and sodium bicarbonate/carbonate to react, they must either be dissolved in water as two solutions poured together, or as two solids in close contact with enough humidity to hydrate the outer layers of the crystals.

When manufacturers make salt mixes, they must therefore be very sure that they've properly dried all of the salt mix components, and the manufacturing facility must also have a dry atmosphere, because a lot of the components of the salt mix are hygroscopic. Hygroscopic means the substance will pull moisture out of the air; a rather impressive example of this is solid sodium hydroxide (lye) - if left out on the counter in a house with ordinary humidity, it will be a puddle in a matter of 30 minutes or less.

So, if a salt mix is kept in an anhydrous or nearly anhydrous state, it will still mix up with very little insoluble calcium carbonate reside for years after it was initially compounded at the manufacturer. However, the plastic bags that salt mix is typically packaged in is not a perfect moisture barrier; technically, neither is the plastic bucket packaging, though it has a far lower water vapor transmission rate (WVTR) than a relatively thin plastic bag.

So when either stored for a long period in its original packaging, particularly at elevated temperatures, or when opened and not effectively re-sealed by the aquarist, the salt mix will start to pull water from the surroundings, and this allows the calcium chloride and sodium carbonate/bicarbonate to react and form insoluble calcium carbonate. This insoluble calcium carbonate will act to form "bridges" between the crystals of the materials in the salt mix, and eventually the whole mass will form one solid clump.

So what does all of this mean for the reefer? First, always start with your mixing container full of RODI, then add salt mix slowly to reach the desired specific gravity. Never start with the salt mix on the bottom of the bucket and add water - the initial solution will be highly concentrated, and the higher the concentration, the greater the tendency for the dissolved calcium chloride and sodium carbonate to react to form insoluble calcium carbonate.

Second, always store your unused salt mix in a sealed plastic bucket, and be scrupulously careful never to scoop it out with a wet container. If you buy your salt in plastic bags packaged in cardboard as I do, buy a 5 gallon plastic bucket at the home store with a lid that includes a gasket. Clothespin the bag closed by folding it over several times (or use a chip clip), then seal the bucket tightly. Store the bucket at room temperature or slightly below, and never store it under the stand for your aquarium; the elevated temperature and humidity will work against you.

If you do have salt that's clumped, you can still use it. You will just get a good deal more insoluble calcium carbonate in the bottom of your mixing bucket, and you will need to test the mixed salt water for alkalinity and calcium content to ensure that you have a starting point that you think you have for your water changes. In an extreme case, you may have 20% - 40% less calcium and alkalinity than advertised by the specific salt mix. If you're keeping fish only, the calcium and alkalinity won't matter all that much. If you're keeping a reef, you may want to add in some 2-part calcium/alkalinity solution to your mixing salt water to raise the calcium and alkalinity to the ranges that you desire.

Happy Reefing.

[LIreefguy]

Originally Posted by dkeller_nc

OK, folks, a little chemistry to clear things up. Billdogg has it correct, I'm just going to expound on his explanation a little.

Unless the salt mix contains organics (there's a few brands that do, but not very many), it can't "spoil" as in go rancid or grow bacteria.

The principal element in a salt mix is, of course, sodium chloride. The principal minor elements are calcium chloride, sodium bicarbonate and/or sodium carbonate, magnesium chloride and sodium or magnesium sulfate.
That's 99%+ of the salt mix. There are many other ionic salts in the mixture, but they are all present in minute quantities, so we can ignore them for this discussion.

As most know, calcium carbonate is insoluble for all practical purposes in pure water. Among other potential reactions, calcium carbonate can be formed by mixing ionic calcium with an ionic carbonate. For our purposes, the principal source of these two reactants is calcium chloride and sodium carbonate/bicarbonate.

To actually get calcium chloride and sodium bicarbonate/carbonate to react, they must either be dissolved in water as two solutions poured together, or as two solids in close contact with enough humidity to hydrate the outer layers of the crystals.

When manufacturers make salt mixes, they must therefore be very sure that they've properly dried all of the salt mix components, and the manufacturing facility must also have a dry atmosphere, because a lot of the components of the salt mix are hygroscopic. Hygroscopic means the substance will pull moisture out of the air; a rather impressive example of this is solid sodium hydroxide (lye) - if left out on the counter in a house with ordinary humidity, it will be a puddle in a matter of 30 minutes or less.

So, if a salt mix is kept in an anhydrous or nearly anhydrous state, it will still mix up with very little insoluble calcium carbonate reside for years after it was initially compounded at the manufacturer. However, the plastic bags that salt mix is typically packaged in is not a perfect moisture barrier; technically, neither is the plastic bucket packaging, though it has a far lower water vapor transmission rate (WVTR) than a relatively thin plastic bag.

So when either stored for a long period in its original packaging, particularly at elevated temperatures, or when opened and not effectively re-sealed by the aquarist, the salt mix will start to pull water from the surroundings, and this allows the calcium chloride and sodium carbonate/bicarbonate to react and form insoluble calcium carbonate. This insoluble calcium carbonate will act to form "bridges" between the crystals of the materials in the salt mix, and eventually the whole mass will form one solid clump.

So what does all of this mean for the reefer? First, always start with your mixing container full of RODI, then add salt mix slowly to reach the desired specific gravity. Never start with the salt mix on the bottom of the bucket and add water - the initial solution will be highly concentrated, and the higher the concentration, the greater the tendency for the dissolved calcium chloride and sodium carbonate to react to form insoluble calcium carbonate.

Second, always store your unused salt mix in a sealed plastic bucket, and be scrupulously careful never to scoop it out with a wet container. If you buy your salt in plastic bags packaged in cardboard as I do, buy a 5 gallon plastic bucket at the home store with a lid that includes a gasket. Clothespin the bag closed by folding it over several times (or use a chip clip), then seal the bucket tightly. Store the bucket at room temperature or slightly below, and never store it under the stand for your aquarium; the elevated temperature and humidity will work against you.

If you do have salt that's clumped, you can still use it. You will just get a good deal more insoluble calcium carbonate in the bottom of your mixing bucket, and you will need to test the mixed salt water for alkalinity and calcium content to ensure that you have a starting point that you think you have for your water changes. In an extreme case, you may have 20% - 40% less calcium and alkalinity than advertised by the specific salt mix. If you're keeping fish only, the calcium and alkalinity won't matter all that much. If you're keeping a reef, you may want to add in some 2-part calcium/alkalinity solution to your mixing salt water to raise the calcium and alkalinity to the ranges that you desire.

Happy Reefing.

Great job explaining this topic. Wanted to say thank you for fully explaining what, and why it happens.

I knew what happens, but not nearly to the degree that you know and wouldn’t nearly explain it such as you did.
It would be more like my parents used to say.
Them: Don’t do that
Me: why
Them: because I said so




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