Planted Tank Guru
Join Date: Jul 2010
Location: Huntington Beach, CA, USA
Condensation comes from the warm water evaporating and condensing on the cooler glass. This leaves the effect to change when the lights are on. Likely the lights will heat the glass?
It will likely change, whether it remains enough to block the light, it will still need to be wiped down at times to avoid a residue buildup.
Personally, I like much more air circulation over the tank top. When you start pumping in CO2 and there is little room for O2 to enter the water at the top, it can get too much for the fish.
Not saying it is a major problem but just another thing to be aware of in case you do want to do a different plan.