emptying res every 3 days . reapply nutes? or wait

basically i tend to empty my resevoir in my aerogarden every few days cos it gets dirty n stuff , just wondering now if i put in my nutes and then decide 2 days later to empty the res should i then add more nutes or wait a week or so ? cos i got told to add nutes every 2 weeks

Add new nutes every time you change out. You can probabally just change out the solution once a week and be fine but the more often you change them the better the plants like it. Of course if you take this too literally it could get very expensive.