Salt mixing and its effects

[09bumblebee]

Working in the medical field with water and various types of what we call dialysate which is a complex prescription with various sodium bicarb, calcium, potassium, and many other ingredients. We were discussing over mixing sodium bicarb so I was testing the theory of over mixing salt if the same effects can happen within salt. Well my conclusion is correct you can over mix salt. So I mixed up 5 gallons for an hr and let sit, I than mixed up another 5 gallons and continued to mix it for 48 hrs. The results were the same. Salinity was the same and all other levels. Such as cal, alk, mag, etc etc. So I than let them sit for a week wondering if levels would drop or evap out. I used the one 5 gal as a water can be but a month later the levels had dropped drastically. All had dropped to 6.2, mag was 1150, and cal was 350. It had a lid and a small power head to keep circulation. This was done with salinity. I usually mix 140 gal at a time and I use in about 2 months or less. Well every time I do a water change I always have to bring my alk, cal, mag, and potassium back up. I don't know if other salt brands do this as well but my 90 almost crashed yesterday. I came home to a frogspawn dead that I've have for 2 years. I checked alk and it was fine cause Its on a dosed. I checked cal and it was 300, mag was 1100. I was shocked to see this. Brought all levels back up over 5-6 hrs cause I didn't want to shock everything. So moral of the story don't mix salt and let sit for longer than a month. I do run a heater and a power head in my big salt tank but crazy to see that the levels drop this much over a period of time. Even being completely sealed.

 

[daverf]

wow, this is really good info, thanks for sharing.

so you're saying that it is best to use saltwater within a short period of time, after it has been mixed - right? i didn't know if you were also saying that you can overcirculate it after it is mixed?

i have noticed heavy precipitate in my brute trash cans when i let saltwater sit too long, or worse when I dose buffer in fresh saltwater within it. maybe this explains it?

so the big question for me is - why would we see this aging issue only in saltwater that is aging outside of the tank? why is it that once you put it in the system, it remains stable? aragonite sand maybe? or is it a problem to let it sit in plastic mixing reservoirs? hmm, so some of those questions were rhetorical but i'd love to know if you (or anyone else) knows the answers.

i wonder if it is the sand. it would be interesting to repeat this experiment with a media bag of aragonite in the mixing reservoir - see what happens...

 

[CRW Reef]

Curious Brain do you have ATOs on these mixing tanks or are you having to add RO due to evaporation? Or ....... are you not loosing anything because of sealed lid?

 

[09bumblebee]

It's not the salinity dropping its the cal, all, and mag, and potassium. That's all I can test for. I'm sure as why we are loosing these levels. I have a chemist major at work that I can talk to as to why these levels would be dropping. I wouldn't let it sit for longer than 3 weeks. I had to add to bring my cal alk and mag back up to where it should be before a water change. I'm going to try this with kent salt and see if brand makes a difference.

 

[jahmic]

Seachem says on their site that overmixing of the salt can lead to a pH drop, which causes precipitation and the resulting drop in levels. As far as why this happens in a bucket and not in our tanks...it'd seem likely that the sand provides substantial buffering to keep the pH levels stable enough to avoid precipitation. Also, being that the pH drop is caused by the introduction of CO2 into the water...if you're running macro in your tank then it's consuming CO2...nuisance algae consumes it as well. That process isn't happening in the mixing bucket.

I've played around with this as well, and have found that higher volumes of salt mixing for an extended amount of time are more stable. I can't imagine what my levels might be after mixing for a month; I've seen a significant drop over a week with 4gal of water in a 5gal bucket. Right now I have about 1gal of water in a 5gal bucket that I've been mixing for 48 hrs just to see what might happen. I'll test it when I go home and see if the levels dropped faster in that small of a volume being overmixed by an MJ1200.

 

[daverf]

definitely looking forward to hearing the results of these experiments.

in my experience, the worst precipitation occurs for premixed saltwater when a buffering agent is added. adding the agent before salt causes the walls of my brute trashcan to go white with precipitate (and also causes the water to stink), not so bad when added after (i use RO as my source). khalis, what you say on PH makes perfect sense, but seems what i've seen runs counter to this?

i have two 30G+ reservoirs. I'll have leftover aragonite media in a few weeks, after I order and build my sulfur reactor. I'm going to try an experiment of aging equal large amounts, one with an aragonite media bag and one without, and see what happens.

 

[Haulin Oates]

Salt mixing and its effects

See, this is why I mix my salt 20 mins before pouring it in my tank!!

 

[280g-reefman]

Great info, always kind of wondered about that. I have always mixed and then did a water change within 1-2 days. Was leaning towards always having a large volumn available but i will just stick with the old method.

 

[Bajamike]

I always try to mix salt and use within 24hrs sometimes thats not always posible but most of the time.

 

[jahmic]

definitely looking forward to hearing the results of these experiments.

in my experience, the worst precipitation occurs for premixed saltwater when a buffering agent is added. adding the agent before salt causes the walls of my brute trashcan to go white with precipitate (and also causes the water to stink), not so bad when added after (i use RO as my source). khalis, what you say on PH makes perfect sense, but seems what i've seen runs counter to this?

i have two 30G+ reservoirs. I'll have leftover aragonite media in a few weeks, after I order and build my sulfur reactor. I'm going to try an experiment of aging equal large amounts, one with an aragonite media bag and one without, and see what happens.

I think my biochemistry is a little too rusty to figure this one out...but, just out of curiousity, what are you using for a buffer prior to mixing your salt?

I also usually try to mix my salt just prior to use...but on occasion I unexpectedly need to pull water from my tank (dips, giving away frags/macros, etc) and it'd be nice to have some mixed salt at temp and ready to go...especially if I ever needed to do an emergency WC. Keeping a 5 gal bucket on hand seemed reasonable, but as I mentioned, my parameters dropped too quickly to make that worthwhile. I decided to try with a 1 gal batch, but expect to confirm my theory that the smaller water volume leads to faster precipitation given the amount of flow that powerhead is pumping out in that little bucket. I did at one point try filling a 10gal QT tank and letting that mix for a week...and although the Alk didn't drop as much, it was just MUCH less convenient than just mixing it in a bucket and carrying that over to the tank.

 

[Ghosty]

wow, this is really good info, thanks for sharing...

Damn, never knew that! I'd already planned on storing RO/DI water pre-salt, but it's good to know not to try salt. I wonder how long Elite stores their RO/DI saltwater? Hopefully they go through it frequently enough for it to not to "settle out".

 

[ailachami]

Salt mixing and its effects

that's why I only mix salt in a couple of hours before using but really its just to bring the temp up to match the tank.

 

[FinsUp]

Damn, never knew that! I'd already planned on storing RO/DI water pre-salt, but it's good to know not to try salt. I wonder how long Elite stores their RO/DI saltwater? Hopefully they go through it frequently enough for it to not to "settle out".

Yeah, I never thought about that! Using their LFS as a source of saltwater might be causing some folks problems keeping their parameters in line, depending on how fast the store cycles through their water, because of the drop in calcium and alk, etc...
Has anyone tested saltwater they bought at a store before mixing it into their system?

 

[Smiley]

Re: Salt mixing and its effects

This is the main reason I use Microbe-Lift reef salt.....it is the same if I use it 20 minutes after mix or one week after mix. IMO it is the best on the market.

 

[ReefCheif]

I use my mixed salt almost immediatly becuase of this reason. I dont let it sit for anymore than 48 hours.

 

[cdrewferd]

I really wonder if this happens with all salt. If that's the case then you can never truely have extra water on hand if you are making it, then using it right away. What if you needed to do a 50% water change ASAP, but then had to wait for your RO/DI to make that much water.

 

[cdrewferd]

This is the main reason I use Microbe-Lift reef salt.....it is the same if I use it 20 minutes after mix or one week after mix. IMO it is the best on the market.

Have you tested this? I would have thought Salinity would be one of the more stable since it's more expensive than the others. Just wondering how you know it's the same.

 

[ReefCheif]

I really wonder if this happens with all salt. If that's the case then you can never truely have extra water on hand if you are making it, then using it right away. What if you needed to do a 50% water change ASAP, but then had to wait for your RO/DI to make that much water.

This is the biggest reason I went with a bigger RO/DI and added a booster pump. I can make enough water for a 50% water change on the 180 (230 gal total volume) in about 6 hours. This does require boiling a small portion of the RO to raise the temp quickly. I had way to manu isses in the past with letting pre mixed water sit.

However this does bring up another point? What abut those pre mixes they sell in stores? Those dont seem to have a shelf life so how is it they are able to pre mix and store it on a shelf without the levels dropping?

 

[09bumblebee]

Have you tested this? I would have thought Salinity would be one of the more stable since it's more expensive than the others. Just wondering how you know it's the same.

IMO salinity is the most unstable. I'm switching I'm tired of seeing low levels after water changes.

 

[Smiley]

ive used seachem, aquavitro, D&D, red sea, and a couple others... always with problems.... Once I switched to Microbe-Lift, all my problems went away... I have been using Microbe-Lift for few years now. I havent had problems with low alk, calc, or mag ever since i switched to ML either. Ive had consistent readings from bucket to bucket and never experienced any settling within a bucket...