Recently noticed my pH was swinging quite a bit in a 24 hour period and replaced my CO2 scrubber media but it didn't help so I figured maybe the rocks in my sump were taking space away from my chaeto (opposite light cycle).
Then today I remembered that I hadn't dumped the skimmate in a couple of weeks. Seemed unusual since I can usually get it full in just 2-3 days.
So I checked and no bubbles.
Had to take the thing apart and clean the needle impeller.
While I was at it I dumped out the tube and guess what - I found a nickel plated key! (probably thrown in by the baby when I emptied the cup)

I wonder if the corroding key could have contributed to my mysterious LPS demise a little while back?

On a positive note not having the skimmer skim for 2 weeks apparently didn't have much effect on my livestock at all. Guess that's the nice thing about not having SPS.

The only noticeable thing was the pH swing due to the scrubber not being able to function without the skimmer!