Nice info! I'm going to start covering the water. After reading that info I think It will be very doable for me to mix like a 5 gal bucket worth of solution and get a top for it and just use like 1 bucket of solution a week or something.
That is exactly what I had started to do after getting this answer.
But I really suggest everybody to buy a bottle of hydrogen peroxide (30%) and use it regularly for desinfection. Remaining nutrients are nice food for any kind of living creatures that hang around. Harmfull or not harmful, nobody likes that stuff.
Good Luck!