not sure how a cal rx could be a hassle? I put media in the camber, set the ph controller, turn on the co2 and set my drip. I don't even test anymore i just watch the clam and the corals. Again not sure how it could be to dangerous if the co2 reg fails it fails in the closed position. All i do is check my drip rate like once a week. I have a 210 gallon with tons of sps and i could not even imagine the cost and hassle of dosing two part even through a dosing pump. I use arms extra coarse high mag media so i don't even dose mag the most important part of all of it is buying quality equipment and media this is not a piece of equipment u want to cut corners with but i started saving money after having it for six months. Below is six months of growth. I lost most of my coral when i had to move my tank from GA to VA. Now things are looking good.