HW errors have to do with your miner. As for the rejects, it's different with each pool on the work being supplied to the miners.
jst curious as to why so many more errors since i switched to kano. is kano pool somehow harder on the machine or something ?
1) Long term, it depends on how close you are to the node you are mining to
see the first post to find a closer node if you are not close to the main node
2) They're random so you may get a run of rejects and then not many.
aside: it could also be when you first connect you get a bunch of "hi" rejects caused by your miner
click on the "Show Details for Invalids:" check box on the Workers->Workers page to see what the rejects are.
3) 11 stales in 24 hours is actually very good.
Over 24 hours there's about 144 work changes, so that means if they are all stale, you are averaging only one stale per 13 work changes or about 1 every 2 hours.
However, certain old versions of Bitmain miners throw away stale shares and don't send them to the pool even though they should.
This can include stale blocks that we can on rare occasions turn into 2 blocks ... ... ... ... ...
Errors are the miner's fault, not the pool