I think it depends on your tank though....or something. Because even with half of my lid covered and misting, my humidity won't get over 30% some days. It must have a lot to do with the temps outside and the humidity in the air too. Temps in DE fluctuate so much...when it gets warmer here on some days...my humidity will suddenly spike up to 40% or 50% in my tanks. Then as soon as it gets really cold out...it drops down to 30%...sometimes even 20%. It's very frustrating. You're actually pretty lucky...aquamentus...because a lot of members complain of having trouble keeping humidity up...especially this time of year.