Am I changing my water too often?

[DillyTrying2Learn]

I have a RDWC set up with 4 sites that are 13gal buckets and a 13gal resivor as well. I have 46 gallons circulating in my system and am doing changes every single week. Is this too often if my PH and PPM/EC is steady and not fluctuating? My water temps are down to 66 when the lights are off and get up to 71 by the time they go back out again and I have more than enough air. Can I just top off for another week and change every 2 weeks or am I asking for problems doing that? 46 gallons each week is a decent amount of nutrients and if I could cut that in half it would be a decent savings.

 

[Bushbandit]

I dump every week
not always but there have been nutrient issues when I’ve left it longer sometimes