Feeding Schedule Problem (maybe)

I have setup a hydro drip, my timer (cheap) only allow me to turn it on and off every 30 min. I know I should feed the plants when the light first turn on, and about 2 hours before they turn off. The problem, I think it's a problem, is that when the pump turns on the slowest drip rate I can achieve is about 175 ml in that half hour period. I am using Sure to grow blocks 4”x4”x4”, inside a 8” net pot, filled in with Hydroton clay pebbles. I was concerned that if I feed the plants 4 or 5 times a day, I will over feed and burn them. Without getting a new timer do you think there is a plausible feeding schedule with this setup.
　

 

Your right.... Just bought it, thanks for the link.