that is strange, the ONLY crystals i've seen grow at all from the clusters i crafted and placed were the flux ones, i was using vis after crafting them, but not a whole lot of stuff that should make flux, i was personally assuming at least for flux crystals they must work the inverse of a battery, always wanting to be as full as possible and taking a small bite out of whatever flux is generated.
all assumptions and yes, seconded, for crying out loud, we really need more information on the aura system in TC6, desperately.
also, might just be me, but there's absolutely no way to purify taint?
just be glad this isn't the classic thaumcraft versions, i guess.... i've literally been run out of at least one or two bases because of taint back when the seals system was still around.
also to be entirely fair, flux has never been easier to avoid early on either, just always have a handful of nether quartz shards to dump into the crucible after use until they don't interact anymore, thankfully they don't contain any aspect pollutants themselves or else we'd really be screwed with flux.
The only way I've seen taint decrease so far is by spawning taint seeds... ideally if you are fast enough to kill them before they start to spit taint in the chunk you'll see the taint decrease because to spawn them a sizable chunk of taint is subtracted from the aura while very little is thrown out by the seeds upon death... still not the safest way, I was planning to put on the roof of my base some automated crossbows to kill as fast as possible any taint seed upon spawn. Also is it just me or there is no way currently to harvest single crystals from the cluster, I tried the old golemancer's bell but nothing (even the cheat thaumonomicon doesn't show a way) I guess it's because it's still a work in progress.