"Do not overmix salt" - Why?

[mjszos]

Basically the title - why does some salt indicate to not "overmix"

Isn't it functionally being perpetually "mixed" once it enters the tank following a water change? What would be the adverse side effect to leaving a pump mixing salt perpetually in a container, is this not fundamentally the same as when it's added to your tank and is constantly being turned over with the other 90% of water volume you combined it with?

 

[BryanM]

I do not know why, but this specific salt is weird. When I got in to this hobby I thought this was my best bet, not knowing squat.

I premixed a brute, used a bit of it, and then it just started to get cloudy. Found out you need to use it within 4hrs or something when mixing.

I've since moved on to Tropic Marin Pro Reef, and I had/have no reason to try and maintain 12 dkh, which is what this salt supposedly mixes at.

 

[Crabs McJones]

That seems weird. Once it goes into our tanks, don't the pumps constantly "mix" the water anyway. I wonder what would be the difference between leaving it in our mixing bucket with a pump running or putting it in the tank with a pump running.

 

[mjszos]

I do not know why, but this specific salt is weird. When I got in to this hobby I thought this was my best bet, not knowing squat.

I premixed a brute, used a bit of it, and then it just started to get cloudy. Found out you need to use it within 4hrs or something when mixing.

I've since moved on to Tropic Marin Pro Reef, and I had/have no reason to try and maintain 12 dkh, which is what this salt supposedly mixes at.

That's odd. I've been using the Coral Pro for ~4ish years now. This piqued my interest as I recently had some mixing in a bin for 3 weeks, tested it and it was perfectly fine (after adjusting salinity a bit).

I have 2 more of their 200g bags in storage at the moment, once it runs out I may look into swapping salts.

That seems weird. Once it goes into our tanks, don't the pumps constantly "mix" the water anyway. I wonder what would be the difference between leaving it in our mixing bucket with a pump running or putting it in the tank with a pump running.

This is kind of my thought as well. As I mention above, I've had this salt mixing in a container for days/weeks on end with 0 precipitation or cloudiness as well as no functional changes to parameters (at least nothing that I wouldn't accept within a margin of testing error).

 

[exnisstech]

I've read about this with certain salts and I think @Randy Holmes-Farley had an explanation but I can't remember the details. Apologies Randy if I'm confused and it wasn't you.

 

[Dom]

Basically the title - why does some salt indicate to not "overmix"

Isn't it functionally being perpetually "mixed" once it enters the tank following a water change? What would be the adverse side effect to leaving a pump mixing salt perpetually in a container, is this not fundamentally the same as when it's added to your tank and is constantly being turned over with the other 90% of water volume you combined it with?

I can't imagine why this would be either.

Maybe they've determined that this is best when using their product for some undisclosed reason?

 

[mjszos]

I've read about this with certain salts and I think @Randy Holmes-Farley had an explanation but I can't remember the details. Apologies Randy if I'm confused and it wasn't you.

Would be great if he chimed in. When I have some more time later today I'll poke around with some of the other big salts and see if I can find any supporting documentation behind this.

Maybe I'm thinking about this the wrong way, but I'm having a hard time connecting the dots as to how the other 140gal in my system aren't precipitating out or causing some "problem" because the pumps run constantly.

 

[Dom]

This is an AI reply to the question:

The recommendation not to mix Coral Pro salt beyond 4 hours stems from its unique formulation, which includes elevated levels of calcium, magnesium, and carbonates (alkalinity). These elements are designed to support rapid coral growth, but when mixed for too long, they can become oversaturated in the water. Prolonged mixing, especially with aeration or excessive agitation, increases the water's exposure to air, allowing it to absorb more carbon dioxide. This can shift the pH and alkalinity, leading to the precipitation of calcium carbonate—essentially, the dissolved elements start forming solid particles, reducing their availability in the solution and causing cloudiness or sediment.

The manufacturer advises a shorter mixing time (typically 0.5-2 hours until fully dissolved, with a 4-hour maximum) to ensure these foundation elements remain in balance and bioavailable for your tank. Mixing beyond this window risks losing some of the intended benefits, as the precipitated compounds won’t redissolve easily. So, it’s less about the salt going "bad" and more about maintaining its optimized chemistry for immediate use in a reef aquarium.

 

[mjszos]

This is an AI reply to the question:

The recommendation not to mix Coral Pro salt beyond 4 hours stems from its unique formulation, which includes elevated levels of calcium, magnesium, and carbonates (alkalinity). These elements are designed to support rapid coral growth, but when mixed for too long, they can become oversaturated in the water. Prolonged mixing, especially with aeration or excessive agitation, increases the water's exposure to air, allowing it to absorb more carbon dioxide. This can shift the pH and alkalinity, leading to the precipitation of calcium carbonate—essentially, the dissolved elements start forming solid particles, reducing their availability in the solution and causing cloudiness or sediment.

The manufacturer advises a shorter mixing time (typically 0.5-2 hours until fully dissolved, with a 4-hour maximum) to ensure these foundation elements remain in balance and bioavailable for your tank. Mixing beyond this window risks losing some of the intended benefits, as the precipitated compounds won’t redissolve easily. So, it’s less about the salt going "bad" and more about maintaining its optimized chemistry for immediate use in a reef aquarium.

Maybe I lack the brains to interpret how this is different in a smaller volume, but in my mind it remains that the water is constantly being mixed in the tank. Would it not precipitate out in the system and not redissolve?

 

[Stevorino]

I've read about this with certain salts and I think @Randy Holmes-Farley had an explanation but I can't remember the details. Apologies Randy if I'm confused and it wasn't you.

^^ Me waiting for Randy to clear it all up for us

 

[Fish Fan]

It's because things like calc and alk will precipitate out of solution and cause the water to go cloudy. The water isn't "bad" perse, but it's milky/cloudy and you're not getting the benefits of the additional calc, alk, etc. this salt contains.

 

[rtparty]

Red Sea Coral Pro precipitates horribly if left mixing for more than a few hours. During my Ultimate Salt Test this was my bin after mixing overnight

 

[Fish Fan]

Maybe I lack the brains to interpret how this is different in a smaller volume, but in my mind it remains that the water is constantly being mixed in the tank. Would it not precipitate out in the system and not redissolve?

I'm not a chemist, but I believe the answer here is that in your tank these minerals are being used and interacted with by other things in the tank. The problem here seems to only apply to over mixing in an otherwise empty bucket.

 

[rtparty]

I asked Randy about this and the belief is in our tank there is phosphate and other elements that will stop or slow this precipitation from happening

 

[rtparty]

I wish I had my comment for more context but this is Randy’s quote:

“Organics and phosphate are well known in the literature to block precipitation of calcium carbonate by making the surface not look like a good seed crystal for more precipitation. That’s how magnesium works as well. I think even whole bacteria can serve this purpose.

Yes, things in 5 are, IMO, a big reason why raw artificial seawater is much more prone to precipitation than is reef tank water at the same basic values for alk, pH, and calcium.

I did an experiment years ago where I found I could boost the alk and pH in a test tube very high using ESV alk part plus raw salt water, plus a polymer known to bind to CaCO3 surfaces (sodium polyacrylate). The same could not be done without the polymer.”



The “things” in 5 were bullet point 5 in a list. I believe it was the phosphate and organics he speaks of

 

[Dom]

Maybe I lack the brains to interpret how this is different in a smaller volume, but in my mind it remains that the water is constantly being mixed in the tank. Would it not precipitate out in the system and not redissolve?

I think you ask a good question!

I was curious to see how AI would respond.

 

[mjszos]

Red Sea Coral Pro precipitates horribly if left mixing for more than a few hours. During my Ultimate Salt Test this was my bin after mixing overnight

That's really interesting. I had it mixing in a black 15G container for about 3 weeks and did not experience this. Granted I'm working on a sample size of 1 specific instance, but this is good to know!

I'll be checking out your thread - I've got 2 more 200G bags of Coral Pro, but I've been thinking about swapping to the TM Pro Reef for some time. It's just a little difficult to find locally, and I prefer to buy from my LFS and support the local community.

I think you ask a good question!

I was curious to see how AI would respond.

I think the comments made by @rtparty quoting Randy make sense, but I'm not a scientist (I just play one on TV).

 

[Pennekampdream]

Basically the title - why does some salt indicate to not "overmix"

Isn't it functionally being perpetually "mixed" once it enters the tank following a water change? What would be the adverse side effect to leaving a pump mixing salt perpetually in a container, is this not fundamentally the same as when it's added to your tank and is constantly being turned over with the other 90% of water volume you combined it with?

Red Sea salt blue bucket has the same introduction to not mix for more than 4hrs.

The only logical explanation I see is they are suggesting to mix at 68 degrees and then bring up the temperature to 77 degrees. Might be something at the lower temperature that makes a difference. I have no idea.

 

[mjszos]

Red Sea salt blue bucket has the same introduction to not mix for more than 4hrs.

The only logical explanation I see is they are suggesting to mix at 68 degrees and then bring up the temperature to 77 degrees. Might be something at the lower temperature that makes a difference. I have no idea.

I do wonder if that plays a part... My water goes up to temp prior to adding any salt...

@rtparty - I've not had a chance to review your salt mix thread, but I am curious if you tested at a specific temperature, and if the results you noticed with the Red Sea precipitating were replicated both at a lower and average tank temp?

 

[Rollnwthdatide]

I do not know why, but this specific salt is weird. When I got in to this hobby I thought this was my best bet, not knowing squat.

I premixed a brute, used a bit of it, and then it just started to get cloudy. Found out you need to use it within 4hrs or something when mixing.

I've since moved on to Tropic Marin Pro Reef, and I had/have no reason to try and maintain 12 dkh, which is what this salt supposedly mixes at.

TPMS is 7dKH, not 12 fyi.