I am baffled by tank situation so as I am once again asking the community for help! I have a 55g tall that is several years old. It's been stable but admittedly, I will get lax on dosing and cleaning. I have some hair black hair algae issues atm but that is not why I'm writing. A couple of weeks ago, I abandoned my Hydor 350 in favor of a Fluval FX4. Felt like the Hydor wasn't pushing as much water and while the FX4 is overkill for a 55g, I have the output turned down slightly. While changing the filter, I also swapped out my Atomic CO2 diffuser with a Nilocg reactor. I have had it running now for a couple of weeks. Here is the specific issue. I am running my Co2 at least 3 times faster than before and even then I'm only getting 6.6 on the Milwaukee probe. Before you blame Milwaukee, I even bought a new probe just to make sure it was doing well. I've been using that same probe for a few years so I was fine with changing it out anyway. But yeah, I can post a short video if you want of my bubble counter on the GLA Co2 but I use to be almost able to count the bubbles. Now I have it as a steady stream. There would be no way to count it. I just don't understand why I can't get my Co2 to drop anymore. I'm not convinced that this Nilocg is the best way to go. I mean, I thought it was as I have read a lot of reviews beforehand. I think I got the 24" with the largest diameter inlet/outlet to accommodate the FX4. The plants are pearling, I think even more than they were with the Atomic. What do you guys think about the Co2 reading though. Are there any circumstances that would prohibit the Co2 levels from rising anymore?