seawater

Does anyone have experience storing saltwater mixed using Aquaforest Sea Salt? I have a 20 Gallon AIO, and the most time consuming part of my weekly water changes is mixing just a few gallons of saltwater. It mixes very quickly, which is convenient. But when it comes to mixing just 3-5 gallons...

I buy water from a local store and just found out it’s collected from the sea. I used to keep it for around 2 months in a container in the dark with no circulation. Never smelled bad so i didn’t assume it was spoiled, but now i worry there are no nutrients and it doesn’t benefit nothing in my...