Calcium reactor issue

[iceman86]

Hey guys/gals, I'm having an issue setting up a calcium reactor. The issue is, when I set my effluent drip rate (let's say 60 drops per minute) 12 hours later it has dropped to about 40 drops per minute causing the ph in the reactpr to lower. I thought the needle valve on the effluent line might be faulty so I opened it up all the way and put a ball valve in line and set it to 60 drops per minute. This was last night, and this morning I'm back to around 40 or so drops per minute. I also unplugged the pump and plugged it back in to see if it would go back to 60 drops per minute but it stayed at 40.

Any ideas?