Default, with no software installed should be a very dul blue/purple?
Looking at mine right now, I wouldn't call it bright by any stretch. Is yours defaulting to another colour?
I haven't been able to find any way to disable outright... I assume Aura can do it, at least in theory, but I avoid using it.
Aura does have problems detecting stuff often, and can even trigger anti-cheat software for some games (used to trigger Easy AntiCheat).