newb ebb & flow question

if you have your plants in net pots filled with hydroton do they need to be covered? (to prevent algae?)

is there a downside to flooding too often? (seems like keeping resources in abundance would be better than almost drying out)

yes.

And the flooding is cycled to give the roots time to aerate unless you have a bubbler under each pot. You will be able to tell if you are flooding too much as the plants will look overwatered just like soil. Generally the cycle is increased as the plant matures, but everyone finds their own #.