Calciumcarbonate forming from CO2 media?

[kilnakorr]

I have a recurring issue, with the airintake of my skimmer getting blocked.
Seems the skimmer design with 90 degree angles isn't very smart when running a CO2 scrubber.
I believe it's the fine dust from the CO2 scrubber media as the build up is hard as rock, and often happens few days after changing the media.
I don't find

 

[KrisReef]

I used to have this happen years ago when I ran DKH elevated, 9 if I remember. It was an older skimmer and I changed it out because I got tired of trying to keep it working. Never had this issue with my Reef Octopus, or any other newer skimmers but I am keeping dkh near 7-8, max.