I would get rid of them.
Like Joe says, you can grow and colour up SPS with Redbugs in your system...BUT I say get rid of them for a few reasons. I had Redbugs in my system around a couple of years ago. They were in my system for at least 8 months. I did notice their population go crazy and then reduce...not sure why.
During the time they were in my system some SPS wouldnt colour up:
SSC and some smooth skinned. The SSC was nicely coloured up before the RB's. Tenuis and Selago etc lost their green base and became brown.
Other SPS lost PE:
SSC and Granulosa and a few others lost PE.
Millepora etc were not affected as far as I could tell. These were still nicely coloured and had great PE.
After I treated for RB's I remember how the granulosa quickly regained PE and the SSC regained PE and colour. Actually, the SSC looked pretty unhealthy...within a week of treatment the SSC looked so much better!
I used to think they are not so bad before. I remember a thread from around 12 years back reefers were arguing over whether RB's are really bad or not. Back then and upto the point before I treated my tank, I thought they arent so bad...and they arent...but they do impact some SPS more than others.
However I would treat my tank right away now if I found my corals were infected with RB's.
All my SPS get a 10 hour triple dose of Interceptor and QT before going in my system now.
For sure ones corals can survive just fine with RB's in the system, but IME not all will be at their best. i didnt lose anything, but have heard of others losing some acros to RB's due to over infestation.
The other thing to realise is that you cannot swap/sell frags...even selling a zoa on a frag plug can potentially infect someone else's system. Not saying you personally, but just pointing out the potential impact.
