Does saltwater go 'bad'?

[glb]

I've been using purified seawater in my tank since I started with corals. I decided to switch to ro with salt mix for more stability. When I was at a new lfs yesterday getting the salt mix, I was telling the guy there about the problems I had with my zoas. He said that natural seawater or salt mix seawater can have some die off of organic material if stored too long, even producing ammonia. I've kept my saltwater sealed in 5g jugs, but it sits for weeks at a time because I have a nano and only change a gallon a week. Is it true that saltwater should be used right after it is bought/made? It makes sense to me but I'd never heard that before.

 

[Eric B]

I don't know about purified seawater but I only mix up salt water that I will be using within 24-48 hours as I know ph as well as other numbers can and do change once it sits for extended periods. I also have a mixing station so I always let the pump mix it up again even if using it closer to the 48 hour mark from when I mixed it. What salt brand did you switch to?

 

[glb]

Reef crystals. I asked around and it seemed to be a good choice for softies and lps, which is all this tank will ever have.

 

[glb]

I don't know about purified seawater but I only mix up salt water that I will be using within 24-48 hours as I know ph as well as other numbers can and do change once it sits for extended periods. I also have a mixing station so I always let the pump mix it up again even if using it closer to the 48 hour mark from when I mixed it. What salt brand did you switch to?

The mixing and using quickly makes sense. My tank will probably be healthier as a result!