Why hasn't a company...

then alkalinity would probably drop.

 

That's exactly what limestone (the kind of rock known as live and base rock) does. The only problem is that it only does it quickly enough to be useful at a pH of under 7.2.

 

the reaction would not be spontaneous at our pH... trust me, this has been explored a lot.

You can either put Ca into an ionic salt which is always water soluble and will instantly dissolve into its ionic counterparts... you can have binders in there that will slow the rate of reaction down but that will only put excess undesired nutrients into your aquarium (phosphate is one of the most common time release binders) and this reaction will not be influenced by the rate of calcium uptake from the corals (aka the rates of uptake will almost NEVER match the rates of dissolution via the "bar" because the binders will not be effected at all by the concentration of Ca in solution)... OR you can have it bound covalently as in some type of aragonite (limestone, coral skeleton, etc.) and this will be a very very slow reverse reaction at pH 8.2 (as blackraven said) since this reaction is more spontaneous into each counterpart the lower the pH is...

Now the only way that would be possible, is you would have to bind the Ca with an inert molecule that is a "buffer" to the saltwater... this buffer would either absorb or dissociate Ca based on the levels in the aquarium and thus would constantly keep your level spot on at exactly the same ppm. The reason this is not possible in aquaria is because this magic buffer molecule would likely contain metals and a lot of carbon strings. The metals would not be aquarium safe and the carbon chains would eventually be broken down by bacteria in the aquarium for food and would thus cause the reaction to take on that of a second order or exponential release rate.

sorry to break it to you but those large corporations would already have this marketed if it were possible. Im sorry for the long and complicated response also, i kinda got carried away with the chemistry :-/

 

Yeah what he said ;D I was going it give that exact answer. J/K, That would be nice if someone could figure it out though.

 

Just to let you guys know of a product I have used. SeaLab #28 Cubes work very well.

Marine Reef Aquarium Additives: SEA-LAB #28 Automatic Replenisher


FWIW, a CA reactor will put alk and CA back into your tank at the rate it is being consumed.

 

Thank you pickupman, I use that in both of my tanks. Cal gets to 500 ppm but slowly drops as the tank uses the block (or smaller cubes for nano use). They suggest Sea-Lab # 14 to go along with the #28 to regulate PH, the #14 keeps PH at 8.3. I like the fact that I could get away from dosing almost every day. If you want more of my experience on my 55 & 14 gal. tanks, I will be happy to give more info.

 

Dingo, very well though-out respones! Thank you

Pickupman22, could you tell us more about your expericences?

 

I used them for a good while and had great results. on my old 75, I didnt test the water, didnt do water changes, and for the last few years, didnt even use a skimmer. it was an old stable system. I just put in the cubes from the 2lb box and added a new cube about once a month or so. the small ones are nice for a nano or a place with no space, the 2kg brick is HUGE! dont get it unless you have a LARGe sump to lay it in. since I am going the CA reactor route this time, I havent bought any yet, but may get that brick again.

OH, and the coral in my avatar was in the tank at the time of these cubes. go search for my reminiscing post in the show off your tanks forum. it has tons of growth photos.