I used to water my plants on a schedule like you, but then i desided to water constantly, because I think it is better to keep the water moving all the time - in nature streams are always cleaner than still water. Also in my opinion this spreads more evenly the liquid through the system and I always know that the PH and concentration of nutes in my reservoir is the same as at the roots of the plants. My plants are growing very well. Just make sure to aerate well.