How long will reserved saltwater last?

[elchopo]

New to saltwater tanks. I purchased an established tank that a LFS maintained for a local church. Now it's mine and I transported 95% of the water and have everything set up. I went to the LFS to buy already made saltwater to fill the tank. However, I did not use all of it. I have 5 or so gallons left in a standard storage container with a lid.

My question is how long would this be considered "good" for? I am not sure if certain things from the container could ruin the saltwater over time or what.

 

[SlugSnorter]

a few days, better to mix your own, the water's alk will drop, and if it evaporates the salinity will go up

 

[IslandLifeReef]

a few days, better to mix your own, the water's alk will drop, and if it evaporates the salinity will go up

First, why would the ALK drop? Are you saying that all pre-made saltwater that you purchase has an ALK drop?

Second, if the water is stored in a sealed container, why would it evaporate?

I have kept unused saltwater in a sealed container and used it later without any issue.

 

[Jmcg89]

How long can I store saltwater after mixing? | BRStv Investigates

For those reefers mixing small batches of saltwater and using it rather quickly after mixing, worrying about the Alkalinity and Calcium parameters shifting is typically not a concern. A growing number of reefers are mixing large batches of saltwater, less frequently and use

www.bulkreefsupply.com

Should be good for a least a couple weeks, I would just double check salinity.

 

[Gtinnel]

I mix up a batch of saltwater and my AWC pulls out of that water for 2 weeks without any issue.

 

[SlugSnorter]

First, why would the ALK drop? Are you saying that all pre-made saltwater that you purchase has an ALK drop?

Second, if the water is stored in a sealed container, why would it evaporate?

I have kept unused saltwater in a sealed container and used it later without any issue.

Its happened to me so In suppose i'm a bit jaded

 

[Randy Holmes-Farley Verified Community Expert]

First, why would the ALK drop? Are you saying that all pre-made saltwater that you purchase has an ALK drop?

Second, if the water is stored in a sealed container, why would it evaporate?

I have kept unused saltwater in a sealed container and used it later without any issue.

Hi alk salt mixes tend to precipitate calcium carbonate faster than the same alkalinity in an aquarium. That is because new salt water lacks some of the things that tend to slow or stop such precipitation, such as organics, bacteria, and phosphate.

 

[Randy Holmes-Farley Verified Community Expert]

New to saltwater tanks. I purchased an established tank that a LFS maintained for a local church. Now it's mine and I transported 95% of the water and have everything set up. I went to the LFS to buy already made saltwater to fill the tank. However, I did not use all of it. I have 5 or so gallons left in a standard storage container with a lid.

My question is how long would this be considered "good" for? I am not sure if certain things from the container could ruin the saltwater over time or what.

Depends on the mix and what is in it.

I used and stored normal IO for a month or more and it was fine, unheated. Heating it and stirring it (causes local heat) can induce more precipitation of calcium carbonate in high alk mixes. Some very high alk mixes can be a problem (CaCO3 precipitation) if heated too much, even overnight.

Some mixes, such as Reef Crystals, have organic matter in them that will change. At the least those should be kept aerated (IMO), and if you want any purported benefit of the vitamins in it, I'd use it before bacteria can consume it.