What happens if you add to much kalk?

[canadawest]

Hey Patrick,

Overdosing Kalk is a little more complicated than just "skyrocketing your calcium". You have to consider that Kalk is a high pH solution and overdosing it (using too much to quickly) would likely cause your pH to increase sharply and your Alk to fall. This swing is far more dangerous to your tank inhabitants than high calcium levels, which I don't think can ever be toxic as it will just precipitate out of your system when it gets too high.

You really have to assess the needs of your individual tank. Check your calcium, pH and Alk levels every other day for a week and dose a small amount of Kalk on the days opposite of your testing. Start with 1 tsp of Kalk mixed in your 2.5gal Aquadose. Set a slow drip that takes all night to empty (about 1 drip every 2-3 seconds) If you are not noticing large swings in your pH or Alk by the end of the week you can increase your dose to 2tsp per 2.5gal (which is what I use on my 100gal tank).

You can reduce the pH swings by dosing at night after lights out, as this is when your pH starts to drop and adding kalk at this time will help to reduce to drop (as the kalk will be increasing your tank's pH)

You can't really super pump your calcium with kalk, as the calcium it actually adds is quite small. Here's a quote from Randy Holmes-Farley:
Also, there's the simple math to consider. Saturated limewater is on the order of 800 ppm calcium. Every time you add 1% (1 gallon in a 100 gallon tank) the calcium will rise by 8 ppm. Thus, if you want to raise it by 80 ppm, it will take 10 days at that rate (assuming that none leaves the water by any route). So you simply can't expect a rapid rise with limewater

So with that in mind you should be more concerned with your pH and Alk levels changing than with your calcium levels skyrocketing. Kalk works best to maintain calcium levels in your tank, but that is entirely dependant on how much calcium your tank is using. Only a test kit and some time with your tank can tell you that answer.