I use kalkwasser in my ato. The evaporation isn't enough to keep up with coral demands. I plan to experiment with adding vinegar & kalkwasser to the ato reservoir . What dangers do I need to look out for? High ph,atc . han thanks !
This can be done, but it's a lot more trouble than it's worth. Due to the nature of kalk you can only get a little bit into the water. Adding vinegar only lets you get a little more in. This is usually not enough to make much of a difference when you have large demands from corals.
Also, kalkwasser should be used in a Nilsen Reactor. Here is an example (offsite) -
http://www.bulkreefsupply.com/reef-octopus-ks100-kalk-stirrer-nilsen-reactor.html
Adding kalk to ato water directly is not very productive, since it tends to precipitate out of solution. A Nilsen Reactor is a sealed unit and it keeps most of the oxygen out of the kalkwasser, so it doesn't precipitate.
If your not currently using a Nilsen Reactor, consider adding one, This is a possible DIY project, so don't feel you need to invest in an expensive ready made one.
If your still having calcium issues that can't be resolved with kalkwasser and the use of 2 part solutions, you best choice then is to invest in a calcium reactor. Yes, it's very expensive to get initially, since you need the calcium reactor, CO2 tank and CO2 regulator, but once your past that, it's very inexpensive to run, and your tank will get the calcium it need.