Water ageing

[LightlyDoesIt]

Hi I am doing a 20 percent water change every 2 days..have bought a moveable builders upvc trunk and pump..I am putting just over the required amount of water with tapsafe and a heater...I lightly cover to stop dust...1 will the cover alter things..2 and is putting an airstone in it a must

[Jason]

Welcome to the community.

Does not really matter if there is a cover on it, unless you are talking about an airtight lid. The air stone helps to circulate the water and keep it from stagnating.

Jason