I want to know if this is ok. I do not think I want to do 24/7 lighting because I hear it is stressful. I am going to put the aerogarden on override to 24/7 then plug a timer into it and put it to 20/4. My question is should i get another airstone so that when the timer switches off it still has an airstone working or is it ok to have it off for 4 hours.