Holding Salt Water for AWC System

[drkcurrent]

I recently set up an AWC system utilizing a 32 gal Brute bin for holding salt water. I am replacing less the 1 g/day so it is about a 30 days supply. I am using Red Sea Blue bucket and mixing the water at room temperature with a powerhead for about 30 minutes. Once mixed I am letting it sit, with a tight lid behind a closed door. I am not heating or circulating the water

I am running into the issue of the salt water yellowing in the storage bin over time. How can I prevent this?

Thanks

 

[ndrwater]

Keeping the water moving with a small power head should help