Alk and Ca

[NewSchool04]

I've been trying to get my Ca levels up for about two weeks, I'm at 380 ppm for Ca and 4.11 Alkalinity in meq/L. If I raise my Ca levels higher will that drop the Alkalinity? Also, I have been using Oceanic salt mix to raise the Ca. I started at 250 Ca two weeks ago and with a 5 and then 10 gallon water change, brought it up to 380. I tested the water before adding and I was getting 500+ in Ca. Is this normal for a salt mix to test so high in Ca?

[aquababy]

Raising calcium levels will not drop alkalinity. Some of the salt mixes I have used are not always consistant in thier chemistry - for that reason I use specific products to raise Ca and Alk rather than using water changes to accomplish the same thing. Magnesium levels (1350 - 1500ppm) are very important as it will stabilize Ca and Alk. Most salt mixes do not have enough magnesium.

[Randy Holmes-Farley]

If I raise my Ca levels higher will that drop the Alkalinity?

Not if you only raise it to 420 ppm or so, and the pH is not too high.

No, it is not normal for salts to have 500+ ppm Ca++, although some folks report that Oceanic salt is that high.

I'd raise the calcium with calcium chloride myself. This article explains the process:

Solving Calcium and Alkalinity Problems
http://www.advancedaquarist.com/issues/nov2002/chem.htm

[lbbudle]

I seem to be having similar problems in my tank I have a 75 gal. Initially I atempted to raise PH ustilizing way too much buffer. In order to reduce alkalinity and increase calcium, I started adding calcium chloride. Not much effect. So now I have done three 15-20g water changes. That seems to have significantly improved things. I was running about 200 calcium and now am running 370 to 400. I was running alkalinity off the scale 13 to 14+. Now I am consistantly registering 4.46 or 12.8 alkalinity. The problem at this point is that something seems to to be suppressing the calcium in tank. I have added from 6-10 teaspoons of calcium chlorine at time and calcium definitely doesn't seem to result in much change. I added a fair amount of magnesiuim (about 30 teaspoons). Magnesium was originally testing at 1200 ppm. In one of the posts I read that once alkalinity was high, it tends to stick to rocks and sand. Is that the case here? The calculators that were given to raise Calcium via the use of calcium chloride. Don't seem to be anywhere near the amount I am adding. My assumption is that something is definitely suppressing the Calcium and elevating the alkalinity. Thanks I appreciate any help I can get

[Randy Holmes-Farley]

Magnesium is not an issue here.

You may have a faulty calcium kit, or you may just not be adding enough calcium chloride.

In any case, with a calcium level of 370-400 ppm and alkalinity of 4.5 meq/L, there doesn't seem to be much problem, although I'd keep adding calcium and not alkalinity for a while longer until the alkalinity drops below 4 meq/l and the calcium stays above 400 ppm. Then I'd stick to a balanced calcium/alkalinity additive system.

If you are at 200 ppm calcium, raise it to 400 ppm calcium, and also preciptate some additional calcium carbonate to bring down alkalinity by 2 meq/L, then in a 75 gallon tank, you'd need to add something on the order of 37 teaspoons of anhydrous calcium chloride, so maybe you just have not added enough.

I do not know what calculator you used, but this one may help:

Reef Chemicals Calculator
http://www.kademani.com/reefchem.htm

[lbbudle]

I have checked the test kit against another friend's test and find identical readings. So that leaves just adding more calcium chloride. I will keep with regimen. The calculator I was using is the same one you returned. I have added more than the 37 teaspoons you referred to plus three 20 gal water changes. Just seems hardly move alkalinity at all when I currently add 6 to 8 teaspoons. Is there something that is artificially holding things at the levels that I am not accounting for? Thank You very much for all your efforts. You must spend a ton of time on the PC!

[lbbudle]

I have checked the test kit against another friend's test and find identical readings. So that leaves just adding more calcium chloride. I will keep with regimen. The calculator I was using is the same one you returned. I have added more than the 37 teaspoons you referred to plus three 20 gal water changes. Just seems hardly move alkalinity at all when I currently add 6 to 8 teaspoons. Is there something that is artificially holding things at the levels that I am not accounting for? Thank You very much for all your efforts. You must spend a ton of time on the PC!

[Randy Holmes-Farley]

Have you tested the calcium in the starting salt mix?

[lbbudle]

I am using Instant Ocean. I just tested the salt and I get calcium @ 300 ppm, Alkalinity at 2.8, Salinity 1.022. I am using Warner Marine Concentrated Calcium. It is actually calcium chloride dihydrate. Does this account for the slow moving of the alkalinity? I thought it was calcium chloride anhydrous version. Do I need to seek the anhydrous version and pitch the dihydrate?
I found a chemistry shop that sell calcium chloride anhydrous (5lbs for $8.00) Or is there any advantage to staying with strictly the reef calcium products??

[Randy Holmes-Farley]

With calcium that low in the starting mix, water changes will continually drop your clacium level, despite your additions.

Part of the reason the calcium is so low is that the salinity is very low. If you raise it to moe natural levels (with a sg of about 1.0264), the calcium will naturally rise.

That said, clacium chloiride is a fine way to raise calcium levels, but I do not know whether particular brands beyond those that I have tested are adequately pure:

Purity of Calcium Chloride
http://www.advancedaquarist.com/issues/mar2004/chem.htm

I seem to recall someone suggesting that that store may sell Dowflake calcium chloride, which is suitable, but I'd confirm that with them before using it. Otherwise, it may not be adequately pure.

There is nothing wrong with a dihydrate. The Warner product is one of the ones that I tested in the article above. You just need to use about 20% more than you would with anhydrous calcium chloride.