low alkalinity

[makana]

Well the tank is clear today and the smell is gone. Amonia and nitrite are going down fast. PH still hasn't changed its 7.9.

How long should I run the carbon? Should I continue to run without the lid? With the lid I didn't need to top off the water because any evaporation pretty much collected on the lid and fell back in. I checked salinity daily and never had it change. Now it has changed half a point since yesterday. I don't mind daily top offs but I'm wondering how you keep fish in and cats out without a top. I also would prefer the lid to minimize evaporation if I go away for a weekend in the summer.