How high can I mix Instant Ocean before I have to worry about precipitation?

[Daniel@R2R]

I unfortunately am not enough of a chemist to help with this question. Thankfully, it looks like answers to that question are starting to be discussed.

However, I will say with regard to how threads are best handled, I'm a fan of answering questions as asked. If there's a caution to add to go with the answer, I'll usually add that too. I have been frustrated at times when asking a question that I'm curious about only to be pointed back to the status quo info that I already knew (and oftentimes upon which the original question was based).

 

[Dan_P]

I unfortunately am not enough of a chemist to help with this question. Thankfully, it looks like answers to that question are starting to be discussed.

However, I will say with regard to how threads are best handled, I'm a fan of answering questions as asked. If there's a caution to add to go with the answer, I'll usually ad that too. I have been frustrated at times when asking a question that I'm curious about only to be pointed back to the status quo info that I already knew (and oftentimes upon which the original question was based).

Yeah, phew the question was finally addressed and kudos to a great forum for providing it.

Here is something you know already. The secret is in how you ask the question and manage the misdirections you receive. Innovation never happens by just getting the answer you ask. It’s the off the rail, left field response that can generate new ideas. Never miss that opportunity to think differently when fielding that “dumb“ question or answer. This forum is really a gold mine.

Have a great day.

Dan

 

[Randy Holmes-Farley]

However, I will say with regard to how threads are best handled, I'm a fan of answering questions as asked. If there's a caution to add to go with the answer, I'll usually ad that too. I have been frustrated at times when asking a question that I'm curious about only to be pointed back to the status quo info that I already knew (and oftentimes upon which the original question was based).

Here are two scenarios. Mine first.

Scenario 1
OP: What is the tensile strength of copper?

Answer: Can we ask why you are asking?

OP: Well, what I want to know is what diameter of copper wire is needed to hang something weighing 27 pounds?

Answer: What do you want to hang with copper wire?

OP: I want to hang a rock.

Answer; Does this relate to a reef tank?

OP: Yes, I want to hang a rock over a cavern.

Answer: So this is underwater in a reef tank?

OP. Yes, I want to suspend a rock over a cavern in my reef tnak.

Answer: Copper would not be the best choice. Stainless steel would be better.

OP: Well, l like the color of copper wire. But maybe stainless can work.

Answer: That seems prudent.

Scenario 2.
OP: What is the tensile strength of copper?

Answer; 32,000 PSI

Fundamentals: Types of Copper and Properties

The copper most commonly used for sheet and strip applications complies with ASTM B370.

www.copper.org

 

[JimWelsh]

Here are two scenarios. Mine first.

Scenario 1
OP: What is the tensile strength of copper?

Answer: Can we ask why you are asking?

OP: Well, what I want to know is what diameter of copper wire is needed to hang something weighing 27 pounds?

Answer: What do you want to hang with copper wire?

OP: I want to hang a rock.

Answer; Does this relate to a reef tank?

OP: Yes, I want to hang a rock over a cavern.

Answer: So this is underwater in a reef tank?

OP. Yes, I want to suspend a rock over a cavern in my reef tnak.

Answer: Copper would not be the best choice. Stainless steel would be better.

OP: Well, l like the color of copper wire. But maybe stainless can work.

Answer: That seems prudent.

Scenario 2.
OP: What is the tensile strength of copper?

Answer; 32,000 PSI

Fundamentals: Types of Copper and Properties

The copper most commonly used for sheet and strip applications complies with ASTM B370.

www.copper.org

Answer: Does the rock weigh 27 pounds in air, or in tank water? If the former, then what is the density of the rock, so we can calculate its buoyancy, and account for its lesser weight underwater? You can probably get away with a thinner wire.

 

[biophilia]

Hi Jimmy,

The public aquarium I work at mixes a saltwater brine at ~50ppt prior to eventual dilution without any precip issues. I don't have any data or experience with salt concentrations higher than that, though. Hope that helps.

 

[Daniel@R2R]

Here are two scenarios. Mine first.

Scenario 1
OP: What is the tensile strength of copper?

Answer: Can we ask why you are asking?

OP: Well, what I want to know is what diameter of copper wire is needed to hang something weighing 27 pounds?

Answer: What do you want to hang with copper wire?

OP: I want to hang a rock.

Answer; Does this relate to a reef tank?

OP: Yes, I want to hang a rock over a cavern.

Answer: So this is underwater in a reef tank?

OP. Yes, I want to suspend a rock over a cavern in my reef tnak.

Answer: Copper would not be the best choice. Stainless steel would be better.

OP: Well, l like the color of copper wire. But maybe stainless can work.

Answer: That seems prudent.

Scenario 2.
OP: What is the tensile strength of copper?

Answer; 32,000 PSI

Fundamentals: Types of Copper and Properties

The copper most commonly used for sheet and strip applications complies with ASTM B370.

www.copper.org

3rd scenario where answer is given but accompanied by caution/caveat (as I proposed in my post.)

OP: What is the tensile strength of copper?

Answer: 32,000 PSI, but if you're considering using copper wire in a reef tank, I'd strongly advise against it.

 

[Randy Holmes-Farley]

3rd scenario where answer is given but accompanied by caution/caveat (as I proposed in my post.)

OP: What is the tensile strength of copper?

Answer: 32,000 PSI, but if you're considering using copper wire in a reef tank, I'd strongly advise against it.

Great. I made an example too easy to see the concerns.

I actually consider my value added here is often to discern what is really needed in an answer instead of a literal answer.

 

[Sisterlimonpot]

@Randy Holmes-Farley I get your point, I won't fall victim to dissecting it in an effort to try and make me right... there's no point.

For over 2 decades I have been appreciative of your contributions to the hobby, I've learned A LOT from you and I have nothing but respect for you. I thank you for your help.

Now, let me get back to my super secret TS classified project... hehe

 

[Daniel@R2R]

Great. I made an example too easy to see the concerns.

I actually consider my value added here is often to discern what is really needed in an answer instead of a literal answer.

And that's fair. I agree that is a great value that you bring to these discussions and is part of your role here. You are an expert in your field and on this forum, and with all respect, my goal was not to challenge the way you handle questions. You do a fantastic job here. I and so many thousands of others are grateful for the way you help.

The point of my post that you quoted was aimed more at general forum etiquette. In general, I think when a person asks a question, it's unhelpful for the answer received (as happened in this discussion before you entered the thread) to be things like "just follow the instructions" when the OP is already aware of the instructions. In this case, the OP was obviously already familiar with the standard mix to 35ppt and was asking how much higher could a mix go before precipitating out. IMHO at that point, it's not helpful to point him back to the standard mix without giving an explanation of why it might be unwise to go higher, but that's basically what happened. My point was simply that when as a community we try to help someone with a question, we should try to actually answer that question rather than telling them that they shouldn't ask it (which is how some of the initial answers or at least the general tone of the thread was coming across...at least that's how I perceived it).

Now, I do definitely think that your role here is different than the average member of our community, and I respect your position as one to not only answer questions, but also to triage those questions and determine (as you said) whether the right question is being asked. I apologize for not making it clear that my point was about general forum etiquette and not a critique of you in the least. I have nothing but respect and appreciation for the work that you do here.

 

[ScubaFish802]

I just read 3 pages of posts only because of the initial secrecy and still a mystery

 

[killer2001]

Yeah, I'm still kinda curious as to what ppt things start to precipitate out at. Does temperature play a role? Atmospheric pressure? Time? Whats really happening at the molecular level? Is precipitate exponential?

All this other banter is just white noise, this is the chemistry forum. lol.

 

[MaxM]

Not true.

Calcium carbonate is above saturation even in normal seawater, and raising salinity can cause precipitation.

I find the exact opposite by experimentation. In a saturated solution of reef crystals the calcium concentration exceeds the concentration of the properly mixed reef crystals by over 20 percent resulting in too much calcium. I don't know about the other minerals because I didn't test them.

 

[MaxM]

What if one wanted to hydrate an entire 50g bag of marinemix into a concentrate to make smaller batches with to avoid potential inconsistencies from stratification of the dry ingredients?

That's what I tried. I mixed half a bag into 5 gal figuring that out would be a saturated solution, ie about 10 times more concentrated than seawater.

Then I diluted it 10 to 1 and got the desired salinity. However, both alk and calcium were much higher than expected for reef crystals. Other stuff may have been off as well which I don't have tests for. To me this means that in a saturated solution of reef crystals, there is excess calcium (at least) that stays in solution.

 

[Randy Holmes-Farley]

I find the exact opposite by experimentation. In a saturated solution of reef crystals the calcium concentration exceeds the concentration of the properly mixed reef crystals by over 20 percent resulting in too much calcium. I don't know about the other minerals because I didn't test them.

I cannot understand what you are saying. What do you mean by a “saturated solution” of reef crystals? Saturation has a specific definition that I’m not sure you are using.

There is no question that every salt mix at 35 ppt is above the saturation point for calcium carbonate (as is natural seawater) unless the pH is below about pH 7.8. That is a basic principle of chemical oceanography.

Being above saturation (called supersaturation) does not mean one will see rapid precipitation of calcium carbonate. In seawater, organics, phosphate and magnesium tend to slow that process to the point where the ocean stays supersaturated.

 

[MaxM]

I cannot understand what you are saying. What do you mean by a “saturated solution” of reef crystals? Saturation has a specific definition that I’m not sure you are using.

There is no question that every salt mix at 35 ppt is above the saturation point for calcium carbonate (as is natural seawater) unless the pH is below about pH 7.8. That is a basic principle of chemical oceanography.

Being above saturation (called supersaturation) does not mean one will see rapid precipitation of calcium carbonate. In seawater, organics, phosphate and magnesium tend to slow that process to the point where the ocean stays supersaturated.

Saturation is the liquid phase sitting above an excess of dry mix. For a single soluble mineral it's something you can look up. For a complex mix it's not so clear. However the concentration of salts in a saturated solution is about 10 X the actual concentration of salts in ocean water. If you dilute a saturated solution of reef salts 10 fold with water you get pretty close to 1.025 salinity.

What doesn't square up for me with you saying that at higher salinity calcium will precipitate out is the following I got by measurement.

Saturated solution diluted 10 fold to 1.025 salinity has a calcium concentration of 580+. Ie, way more than expected.

 

[Randy Holmes-Farley]

Saturation is the liquid phase sitting above an excess of dry mix. For a single soluble mineral it's something you can look up. For a complex mix it's not so clear. However the concentration of salts in a saturated solution is about 10 X the actual concentration of salts in ocean water. If you dilute a saturated solution of reef salts 10 fold with water you get pretty close to 1.025 salinity.

What doesn't square up for me with you saying that at higher salinity calcium will precipitate out is the following I got by measurement.

Saturated solution diluted 10 fold to 1.025 salinity has a calcium concentration of 580+. Ie, way more than expected.

I don’t agree with some of your assertions about the 10x comment. Seawater is well known to already be above saturation of calcium carbonate, and I showed the data that calcium sulfate is saturated at about 3.8x. If you got 10x to be stable, I expect you created a supersaturated solution that might be unstable if you wait longer.

Many reefers, including me, find even 35 ppt IO to be unstable with respect to calcium carbonate, precipitating over time as it sits. Other salt mixes do this too, and some claim the mix is unstable to precipitation (like Red Sea Coral Pro).

I cannot understand any rationale for your claim that making a concentrated salt solution then diluting it causes calcium to be higher than if made directly to that salinity.

BUT, precipitated calcium sulfate can redissolve if you dilute it back to 35 ppt, unlike calcium carbonate.

 

[Gp!]

Intrigued with the question and devastated not to know the answer for instant ocean or some other common salt after reading so many words lol

 

[MaxM]

I don’t agree with some of your assertions about the 10x comment. Seawater is well known to already be above saturation of calcium carbonate, and I showed the data that calcium formate is saturated at about 3.8x. If you got 10x to be stable, I expect you created a supersaturated solution that might be unstable if you wait longer.

Many reefers, including me, find even 35 ppt IO to be unstable with respect to calcium carbonate, precipitating over time as it sits. Other salt mixes do this too, and some claim the mix is unstable to precipitation (like Red Sea Coral Pro).

I cannot understand any rationale for your claim that making a concentrated salt solution then diluting it causes calcium to be higher than if made directly to that salinity.

BUT, precipitated calcium sulfate can redissolve if you dilute it back to 35 ppt, unlike calcium carbonate.

I can't understand why the saturated solution once diluted should be higher in calcium either. My alk and pH we're also higher in the "rehydrated" solution as well. Since I didn't test any of the other minerals/salts, it could well be that many things were redistributed during the saturated solution phase.

Do you know what happens when you do the experiment in reverse, ie, what order do elements precipitate when evaporating salt water? For example, do trace elements stay in solution in concentrated saltwater while more abundant elements come out of solution because they were already near saturation?

 

[Randy Holmes-Farley]

I can't understand why the saturated solution once diluted should be higher in calcium either. My alk and pH we're also higher in the "rehydrated" solution as well. Since I didn't test any of the other minerals/salts, it could well be that many things were redistributed during the saturated solution phase.

Do you know what happens when you do the experiment in reverse, ie, what order do elements precipitate when evaporating salt water? For example, do trace elements stay in solution in concentrated saltwater while more abundant elements come out of solution because they were already near saturation?

I see we never answered this. Are you still looking for answers?

Most seawater data on precipitation at different salinity comes from evaporating seawater. Since that is a big industrial process for making chemicals from seawater, it is well studied.

 

[MaxM]

I see we never answered this. Are you still looking for answers?

Most seawater data on precipitation at different salinity comes from evaporating seawater. Since that is a big industrial process for making chemicals from seawater, it is well studied.

I still don't fully understand what's going on when you mix a multi salts and mineral mixed crystal with water until you get to what appears to be a saturated solution. Ie, a solution where you still have undissolved salts in the bottom.

Does each mineral and salt go into solution at it's own rate or is there an effect of the other salts/ minerals on the rate of mixing?