Getting my Calcium/Alk/Mag correct

abecker · Oct 6, 2015

I recently purchased a Red Sea test kit to test for Cal/Alk/Mg. On my first test yesterday my parameters were:

Salinity: 1.024
Calcium: 365
Alk: 7
Mg: 1240

Going off of the chart on https://www.reef2reef.com/threads/o...-reef-aquarium-by-randy-holmes-farley.173563/ my parameters are a little low. I have a 125 gallon DT with a few LPS corals currently, but I am looking in to getting more LPS and a few SPS corals so I want to get comfortable checking and correcting these levels early on. Is there much of a difference using Sodium Bicarbonate and Calcium Chloride that I mix with water and add to the tank vs some pre-made mixtures like the Red Sea A/B/C?

redfishbluefish · Oct 6, 2015

The major difference is that your wallet will be happier with the DIY mixed stuff. If you pH is running a little low, use sodium carbonate instead (cooked sodium bicarbonate at 350 for one hour).

BRS sells the chemicals, but I still prefer buying baking soda (sodium bicarbonate), at one of the big club stores and cooking it myself. I get 13 pounds for somewhere in the area of six dollars.

abecker · Oct 6, 2015

That was my assumption with the DIY stuff. I don't need to raise my pH, so it sounds like sodium bicarbonate is the way to go. If baking soda is no different than the sodium bicarbonate sold from BRS then that gives me a good excuse to go to Costco to pick some up and of course swing in the LFS that is next door to it.

Randy Holmes-Farley · Oct 6, 2015

If you raise the salinity to 35 ppt as recommended by Red Sea (since you mention their product; sg = 1.0264), the values for calcium and magnesium will get a lot better. Calcium will hit 402 ppm and magnesium will hit 1364 ppm.

As to the difference between using those supplements, I don't think you will see a difference. BRS uses pharmaceutical grades, and so it is unlijkely that Red Sea uses a better grade.

Red Sea does add some other chemicals into the ABC products (such as strontium), but I'm not sure you can see a difference due to them.

abecker · Oct 6, 2015

Randy Holmes-Farley said:
If you raise the salinity to 35 ppt as recommended by Red Sea (since you mention their product; sg = 1.0264), the values for calcium and magnesium will get a lot better. Calcium will hit 402 ppm and magnesium will hit 1364 ppm.

As to the difference between using those supplements, I don't think you will see a difference. BRS uses pharmaceutical grades, and so it is unlijkely that Red Sea uses a better grade.

Red Sea does add some other chemicals into the ABC products (such as strontium), but I'm not sure you can see a difference due to them.

The values you mention by increasing my salinity, is that due to the calcium and Mg in the salt mix, or does increasing salinity have a direct effect on those two values? I mentioned red sea just because their products seemed like a more expensive path than using something like the BRS powders mixed with water. I am currently using IO Reef Crystal salts.

Randy Holmes-Farley · Oct 6, 2015

abecker said:
The values you mention by increasing my salinity, is that due to the calcium and Mg in the salt mix, or does increasing salinity have a direct effect on those two values? I mentioned red sea just because their products seemed like a more expensive path than using something like the BRS powders mixed with water. I am currently using IO Reef Crystal salts.

When you raise salinity by adding salt or by removing water (by evaporation) the effect is the same: more of everything per unit of salty water.

I don't think there's any problem with the BRS products for calcium, alkalinity and magnesium.

abecker · Oct 6, 2015

Randy Holmes-Farley said:
When you raise salinity by adding salt or by removing water (by evaporation) the effect is the same: more of everything per unit of salty water.

I don't think there's any problem with the BRS products for calcium, alkalinity and magnesium.

That makes sense, forgot that it was being measured in ppm.

abecker · Oct 19, 2015

My salinity is up to 1.025 sg, and alk is now at 6.58 dkh and calcium is up to 380 ppm. I am going to retest tonight to make sure those numbers are correct. I started using kalk in my ato, I added 2 tsp to 5 gallons of water. The ATO still had about 2 gallons of water in it so it is a pretty weak solution. If those numbers for alk and calcium are correct, is it best to use baking soda to raise alk separately from calcium and then let the kalk keep both stable?

Randy Holmes-Farley · Oct 19, 2015

How long have you been using the kalk in the ATO?

abecker · Oct 19, 2015

3 days

Randy Holmes-Farley · Oct 19, 2015

I'd increase the amount of calcium hydroxide in the ATO.

You can make a one time correction with baking soda, but that will still likely leave the need to adjust the ATO.

abecker · Oct 19, 2015

Do I need to worry about calcium getting too high from the calcium hydroxide?

Randy Holmes-Farley · Oct 19, 2015

Not in the short term. Alkalinity will always get too high first.

In the very long term (months to years), calcium will slowly climb, but you need not worry about that now.

abecker · Oct 19, 2015

Thank you!

Randy Holmes-Farley · Oct 19, 2015

You're welcome.

Good luck and happy reefing.

arman · Oct 19, 2015

Red sea has a product named reef success CALK that it has mentioned without affecting PH.
And its an alternative fot c choloride and alkanity buffer.
I think it can help you too.

Randy Holmes-Farley · Oct 19, 2015

arman said:
Red sea has a product named reef success CALK that it has mentioned without affecting PH.
And its an alternative fot c choloride and alkanity buffer.
I think it can help you too.

It seems like that might be a discontinued product. The Red Sea web site no longer lists it that I can see, and vendors like Marine Depot say discontinued.

abecker · Oct 19, 2015

Wouldn't regular baking soda have a similar affect since it only lowers ph slightly. On the topic of baking soda, I have double acting baking soda that has some other ingredients besides sodium bicarbonate. Is it safe to use double acting or only use the regular baking soda?

Randy Holmes-Farley · Oct 19, 2015

One can easily make an alkalinity supplement that has no impact on pH (with mostly sodium bicarbonate and a little sodium carbonate), but generally, most people benefit from a pH rise and so most people use sodium carbonate.