2 Part Calcium Buffer Question

[strout]

My LFS man has me putting one capful of each in my tank 2 times a week. My ?? since I don't have any hard corals in my tank, just Zoas and polys, do I need to be doing this? I was wondering if the calcium was bad for my zoas and polys. Thanks for your time

[kristo]

it would be best... it would be either that or you would have to do weekly water changes to keep calcium in the tank. or you and take a spoonful of kalkwasser and mix it with cold RO water in a gallon jug. stick it in the fridge. as the H2O level drops, top it off with the kalkwasser jug and since its cold it releases the calcium slowly as the water warms up in the tank. been doing for quite a few years!!! works for me!

[strout]

Well, I have two opinions, the one Kristo gave me and one in a PM. These two opinions differ from one another, how about a third opinion. I do a water change of 20g every week, if that info helps. Like I said, I am not against doing this, its just someone told me that Zoas & Polys don't like the same type tank water that SPS corals do and since I have all Zoas & Polys in my tank, I don't want to do anything that will inhibit their growth, by having to much calciumin the tank.

[Neuticle]

You need to test for alkalinity and figure out how much buffer you need to add. As soon as you figure out a pattern, you won't need to test anymore.

Every tank is different, and there is no "rule of thumb" for adding buffer, you need to do tests for a couple of weeks. Carbonate alkalinity tests are cheep (~$10 or so for the API kit). Once you figure out how much buffer your tank consumes every day, you can switch to testing every month or so, just to confirm everything is going well.

I'd recommend forgetting about Calcium levels, two-part is primarily a buffer, not a calcium additive. It may seem counter-intuitive, but if you keep up on water changes, you can completely forget about calcium until you have a ton of big stony corals or clams.

Magnesium plays an important roll in buffering as well, if your buffer seems like it's not working (i.e. add a ton and pH remains at 8.0) you likely have a Mg deficiency. If you use Instant Ocean salt, you should keep an eye on this as well.

[kristo]

also... what size is the tank?

and regarding to other methods... its really according to the tank my friend. i am selling a 100 gallon and it ran without any additives what so ever and never had a problem from zoas to montipora capricornis. So i agree with Neuticle and to test the water.

[strout]

I have a 125 g tank, and thanks for the advice,

[Amphiprion]

You need to test for alkalinity and figure out how much buffer you need to add. As soon as you figure out a pattern, you won't need to test anymore.

Every tank is different, and there is no "rule of thumb" for adding buffer, you need to do tests for a couple of weeks. Carbonate alkalinity tests are cheep (~$10 or so for the API kit). Once you figure out how much buffer your tank consumes every day, you can switch to testing every month or so, just to confirm everything is going well.

I'd recommend forgetting about Calcium levels, two-part is primarily a buffer, not a calcium additive. It may seem counter-intuitive, but if you keep up on water changes, you can completely forget about calcium until you have a ton of big stony corals or clams.

Magnesium plays an important roll in buffering as well, if your buffer seems like it's not working (i.e. add a ton and pH remains at 8.0) you likely have a Mg deficiency. If you use Instant Ocean salt, you should keep an eye on this as well.

That isn't necessarily true. You actually add the same number of calcium ions as you do carbonate/bicarbonate ions. The only difference is that it takes much more of the calcium additive to make a difference, since you are dealing with an extremely large calcium sink in seawater (420 ppm is a lot by all standards). There is a tiny sink for alkalinity, on the other hand and therefore it is depleted much more quickly. The scales for measurement also cause this variance in perception. In calcification, 20 ppm of Ca++ is used per 1 milliequivalent of CO3--/HCO3-, which equates stoichiometrically to a 1:1 ratio, hence the rationale behind the 2 part additions. Alkalinity is just a more useful measure when determining dosing schemes since it is the most easily affected for the above reasons. Calcium should still be tested, however, since it may be imbalanced from the start.

Also, while alkalinity can influence pH until an equilibrium is reached, it is mostly independent in our circumstances. Freshwater planted tank enthusiasts demonstrate this when they manipulate CO2 concentrations based on a fixed alkalinity and variable pH. CO2, in fact, is mostly what accounts for the lower pH shifts. Magnesium should be added after verifying that it is below typical levels (~1280 ppm or less). Magnesium will be independent of pH, but will be reflected in calcium and carbonate/bicarbonate solubility.

[Neuticle]

When I used Kent Marine 2-part, it drove me nuts. My calcium levels would be fine but my Alk and pH would be off. Nobody in town could help me, I had to read up on buffering and eventually discovered it was my cheapo salt giving me a mag deficiency.

I still use IO salt, but I add magnesium to 1400ppm when I mix a batch. I've stopped using 2-part and just keep up with water changes and top-off with kalk water, it's much easier for me, and I don't make a mess. Since my alkalinity is depleted much faster than my calcium, I simply rely on water changes for calcium.

Amphiron- If CO2 levels in your reef tank are messing with your pH, you've got some big problems.

[Amphiprion]

I still use IO salt, but I add magnesium to 1400ppm when I mix a batch. I've stopped using 2-part and just keep up with water changes and top-off with kalk water, it's much easier for me, and I don't make a mess. Since my alkalinity is depleted much faster than my calcium, I simply rely on water changes for calcium.

Amphiron- If CO2 levels in your reef tank are messing with your pH, you've got some big problems.

Many of the salts available are terribly deficient in calcium, including Instant Ocean.

I am afraid CO2 is one of the biggest determinants of final pH in our aquariums. It can and does make a huge difference, especially in houses where CO2 concentrations are higher. In fact, most pH problems can be attributed to it. I guarantee you will find measurable quantities of CO2 in your tank, unless you have significant algal growth (either in a refugium or in-tank) or use lots of kalkwasser, which reacts with CO2 to form bicarbonate. It is definitely there and common. Beyond that, CO2 equilibration is why your salt mix isn't caustic after allowing it to sit circulating for a while. It is also why RO/DI water is never at pH 7.0.

Also, if it causes problems, why does it affect oceanic pH and why do tanks do well with calcium reactors, which almost always bleed residual CO2?

[Neuticle]

I've got so much circulation, I doubt there is anymore suspended CO2 in my tank than there is in the house.

[Amphiprion]

I've got so much circulation, I doubt there is anymore suspended CO2 in my tank than there is in the house.

Yes, your tank is probably very equilibrated with the house, which most likely has elevated levels of CO2. I have boatloads of circulation (10000 gph in a 40g tank) and I still have detectable CO2 concentrations (via the aeration test). I even regularly leave windows and doors open and there are still detectable levels due to in-house concentrations.

[Neuticle]

Probably some detectable levels of nitrous in there too, me and my fish hit whippets together after work.

[kristo]

red sea salt! whoop whoop!

[snoopdog]

And make sure you wait a few minutes between putting each part in. For years I put both in at the same time in my sump. The aragonite was one solid sheet when I cleaned that tank out.