How can you tell right amount of water?

12:42 pm in Getting Started, questions, Seeking Advice, Version 3.0 Modular Airlift Columns by JBK

So I have a simple version 3 window farm set up in my window. I have the timer that turns on every 15 mins for 15 mins as they say to do in the instructions, but my plants just dont seem to be liking it. How can I tell if I don’t have enough water (the pump isn’t pumping fast enough) or too much water? Can you have too much water?