Quote Originally Posted by skunkydelight
depending...you don't have to actually clean it till after the grow is finish...i would change the water/nutes every week to 10 days while in flower...you should know where you want your water level, so if it drop below there, top it up...that simple.
-sD
every 7-10 days period. veg and flower...good advice...most recommend topping off with ph'd rowater or whatever water you use, rather than using nute recipe, because of possible toxic levels/ppm's of one nute or another...hope this helps.lw