how often should i nute up?

i'm working a black bucket set and i change my rez about every week but my plants suck up water like crazy and i top them off several times a week i'm wondering if i should add nuts in the top off or just stick to when i change my rez....holla back...thanx

I just add water.
Check your PPM

^^What he said. If you go arbitrarily adding nutrient solution during your top offs, you can create dangerously high amounts of specific nutrients. Cannabis does not uniformly consume equal amounts of the nutrients you put in the solution. So if for instance, your plants are consuming a lot of nitrogen, but not as much potassium, you can actually cause a nute burn situation by introducing more potassium than the plants need. Stick to regular nutrient top offs when you change your reservoir out all together. It makes things much easier.

thanx for the knowledge its greatly appreciated!

fox farm baby!