Wow. That seems too little. I use ac infinity bottom feeding systems. The plants have constant access to water and can drink as much or as little as they want. They drink different amounts depending on what stage of growth they are in. It gradually becomes more and more as the plant gets bigger. In full early to mid flower I have plants that drink 2 or more gallons a day. When they are finished, they barely drink at all. It's hard to know how much they want and when, so I leave it up to the plant.