View Full Version : Dosing Problems: Calcium Alk

09/28/2010, 11:12 AM
So, I have been trying to get my water used for my waterchanges to ideal calcium and alk readings. I use instant ocean salt, so calcium is always low. I have a 2-part dosing products by brightwell, however, I thought I would just dose calcium in the instant ocean to raise it. After doing this, my calcium is decent...440, but Alk is low. However, when I dose the Calcium and then Alk....hoping to raise both, my water gets really cloudy and even the powerhead I am using to mix the water looks like it is covered in snow..a thin hard white buildup. This doesn't seem good.... Is it just not possible to get both Calcium and ALK at high levels? I wanted to do this for my waterchanges, rather than deal with dosing my tank itself, hoping if I get high levels of both, it would help my main tank slowly throughout time as I do a 10% waterchange. Plus, I feel if I could get it right, my waterchange levels would be more consistent.....any help for a dosing newb?

BTW- I also have oceanic salt....thought about mixing 50/50 with Instant Ocean for a good balanced reading....however, not sure this is wise...

09/28/2010, 11:22 AM
It is not recommended to adjust alk levels in your salt mix. It is better to increase your alk in the tank in a much larger volume of water. If you are using a high pH alk supplement like baked baking soda (soda ash or sodium carbonate) this will cause a large increase of pH where it is added, especially if you just pour it in. I would use baking soda (sodium bicarbonate) to increase your alk level in your tank and if you choose to try in your salt mix. Baking soda does not increase the pH. The increase in pH is what triggers the precipiation of calcium carbonate. ;)

09/28/2010, 11:23 AM
You might also want to check your magnesium. If you are having trouble maintaining both without swings, then your magnesium might be off also.

09/28/2010, 11:28 AM
So it seems, cal and alk play a balancing role...raise one and the other decreases....so if you dose a 2-part, trying to raise both....won't they just cancel each other out and do nothing? I guess I will steer clear from dosing my newly mixed salt water and try dosing the tank....but the problem is Alk in my tank is low...but calcium isn't high...it is borderline low as well....390...how do I successfully boost both in my Display? Add the two part and re-test hourly? Add part A then part B a day later....or again, won't they just cancel each other out?

09/28/2010, 11:36 AM
Some hobbyists claim when you add calcium choride especially to smaller volumes like your salt mix container, it can reduce the alk level a bit. FWIW, I have experienced this. Perhaps this is a result from just dumping the calcium chloride in at one time. I don't completely understand the chemistry regarding this.

The alk level of IO is high when mixed to a salinity of 1.0264, so any drop in alk I experienced from adding calcium chloride was not a problem since the salt mix still remained high in alk. I don't understand what your are doing to cause low levels of alk using IO, unless your test kit is bad or you got a strange batch of IO.

09/28/2010, 03:22 PM
So it seems, cal and alk play a balancing role...raise one and the other decreases....
That's not quite true. Adding calcium will not lower alkalinity any measurable amount as long as magnesium, alkalinity, and calcium are in reasonably good shape. The same goes for magnesium. Dosing alkalinity will not lower calcium to any measurable degree as the parameters are okay and the pH isn't forced too high.