There is a bee that can raise the vis levels I think. But it's really slow. And it's very easy to get pissed off and shove some magic frames in it to make it work faster (and at that moment you realize that you just shot a ton of flux into the aura).
Also, from personal experience, aura is infinite. Even without crystal clusters.
It recharges slowly, but it still recharges. Meaning that 100 tiny vis nodes could be better than all of them combined.
My base lost all it's aura nodes in a reset, but there was one small one nearby. I completely destroyed it with my repair 2 damaged tools, but when I put them in a chest elsewhere the aura started to regenerate. I had goggles on, and nothing was being sent to it.