Mixing saltwater

[Scutterborn]

I keep a 20 long full all the time for my changes. After a water change (3 gallons) I refill and resalt the 20L. My water ages for weeks before use. I use a MJ1200 power head and a MJ600 with a Venturi for oxengenation. I check the SG the day before a WC and adjust if needed. I also keep it covered with glass tops.