i use flood tables. you change you nuitr. every two weeks. we use strong chems gh bloom and gh micro, called the lucus form. we also put other atitives in as well. every other day i like to go in re ajust the nuitrent level and ph. if you have a 2000 dollar brain you can have the machine monitar and self inject but you should at the very least change the water in the res every week.