Bubble magus dosing pump issue

[dolpator]

I have been running this doser for about 2 years now, and I haven't had any issues with it. About two weeks ago a head unit blew. I replaced the head unit, and went about my business. Well since I have been having alk swings like crazy. So I ran a test last night. My dosing schedule is 54ml over a 24 hour period. I removed the tube and put it into a container and ran it normally. It tan 106ml over a 24hour period. Any suggestions. Was think it could be the head unit, but it was brand new.

 

[xaxiu]

Could be. Think of tube does stretch over time. Don't assume they dose same amount