i want to know if a 10% or 20% water change will replace calcium that is lost in your tank , i know that the calcium must be at about 420mg/l if it drops to 300mg/l will a water change replace the lost calcium or mus calcium be added ?
Hi Robert! You can safely raise your Ca using Calcium Chloride between 380 - 420. Bear in mind, when dosing plain Ca, you will be dropping you Alk. So keep an eye on your Alk and adjust using Bicarb or a Buffer.
http://www.marineaquariumsa.com/showthread.php?t=6348thanks will do how do you dose bicarb
You run the risk of precipitation. You also need to remember that your calcium levels are tied in with your alkalinity and magnesium levels, if your magnesium is too low then this will interfere with trying to increase your calcium levels. The whole idea of this is to get everything in balance, if one parameter goes out of whack it could be disastrous.
Test your magnesium level and get it up to between 1200 and 1400, you can safely increase magnesium by 100ppm per day. Once your magnesium is correct you can then work on your calcium and alkalinity.
Test your alkalinity and let us know what that is.
If you add one supplement today, it is best to wait 24 hours then test again to see what the level is at.
The way I do it is to add calcium, wait 24 hours then test calcium and alkalinity, add alkalinity supplement and wait 24 hours then test both again, I do this every 2 days until my levels are in check. I increase my calcium by about 20 to 30ppm per day.