We basically know 4 different methods to provide the used calcium to the tank system again:

Both solutions are kept by itself separate chemically stable. There each calcium ion like from above equation clear two hydrogen carbonate ions required in order to form calcium hydrogen carbonate, is to be applied ever considering the element masses gramme-molecule a weight ratio of 7 for 8 (calcium chloride dihydrate to sodium hydrogen carbonate).

CaCl2 + 2 NaHCO3 = Ca2+ + 2HCO3 + 2 NaCl

Calcium chloride + sodium hydrogen carbonate = calcium + hydrogen carbonate + common salt

Per grams calcium we have approx. 2,9 g of common salt! Towards they that for calcium and for hydrogen carbonate ions, that through Kalifizierung and skeleton construction they are used, however, is concentrated the salt in the tank water. At the first look this appears negligibl, at the first look, these salts (sodium + chloride) are in any case the main components of the sea water.

The resultant density rise can indeed be compensated by water alternations, not however, the circumstance of the individual ions to each other. At the first look is conveyed quantity indeed very small not to nevertheless underestimate however converted for the whole year

It is today fuzzy to what extent the tolerance of invertebrates goes, this change a balance existing since year millions tolerate.

The effort of saltfree marine salt how for example manages partial relief available from Tropic marin. This shift can be cancelled by use of this salt at water alternations again. 36,8% of the plagued quantity remain as salt in solution of this quantity must be added to again 42,3% of saltfree sea salt.

The previously mentioned method therefore, presupposes, that the aquarist that Ion-composition knew and/or permanent checks which lots he must balance. Every aquarist can only answer does and/or he wants whether to in the long run do really this by himself. Beyond it during a longer time, this method will be very expensive.
 
 

no doubt, the calcium hydroxide extra is the oldest customary method and was from Wilkens already into the 70ern propagated. Calcium hydroxide is a saturated solution from calcium hydroxide Ca(OH)2 and waters. It makes set up of the ions required for Kalifizierung nonetheless only one available, Ca2+, therefore the calcium ion, disturbing ions as in the case of method 1) however, are omitted (the resulting OH Ionen are neutralized through the bumper capacity of the water if not be over-proportioned).

The equation for the reaction looks as follows here:

If free carbonic acid is available, following in calcium hydroxide run further reflexes off:

Ca2+ + 2OH- + CO2 = Ca2+ + CO3/2- + H2O and long Ca2+ + CO3/2- = that it falls for pH value CaCO3, i.e. by supply of carbonic acid, our calcium as calcium carbonate is cancelled. Is it less than 10, conducts the part of Ca2+ only 5 to 6 mg/l, at this value is the calcium hydroxide virtually useless. Therefore, applied calcium hydroxide must always be kept firmly for this reason in a locked manner since it attracts on account of its basic pH-value CO2 of air.

If the calcium hydroxide is added to the tank, calcium hydrogen carbonate results (CO3/2- and HCO3 are contained in the tank water already) Ca2+ + HCO3 = Ca(HCO3)+, this is of course dependent on the available HCO3 quantity.

At stepping of the solubility limit (extra of too much Ca2+ or HCO3) precipitate CaCO3 milk cloudy.

The hydroxide is strongly basic and lets the pH climbing for value, with saturated calcium hydroxide to pH (1,26 g solve themselves in 1l water of 20°C), 12,4. Therefore, it may never be added at great quantities since it too strong pH - rise in the tank it can come since the OH ions of the bumper system can then be neutralized no more.

Because of the alkaline pH it should be added only in dark phases (pH because of CO2 is least production) and only in small quantities ("droplet means '') .

A further advantage of this method to be mentioned is also the falling out of organic phosphates.

Would be allowed to instability be considered to be a greatest disadvantage of the calcium hydroxide method therefore, it is most effective to apply it daily again. This combined with the droplet means to be recommended (with a 700 l tank can be gone out as a empirical value of a requirement of 5 1/ day), that nevertheless requires a not unimportant daily expenditure, moreover, make this method quite sensitive about different motivation situations of the hobbyist!
 
 

distinguishes from previously mentioned calcium hydroxide extra by additional CO2 entry into the tank. The added CO2 sets up the second available basic module of Kalifizierung. Is prevented by a control that the pH-value in the tank increases over the adjusted tolerance value upwards or below.

One very good electronic measuring and control system (gauging accuracy, not the showed accuracy!) are an absolute necessity since a wrong CO2 proportioning can have catastrophic results for the system.
 
 

is the supply of calcium hydrogen carbonate by means of calcium reactor. In this calcium carbonate which is filled in the form of coral skeletons by supply of carbonic acid solved and therefore both elements of Kalifizierung again is freed: Ca2+ ions and bicarbonate. The equation for the reaction is practical like Kalifizierung (see above).

It first, as one came to the idea, the water not only onetimes but to guide permanently over the substrate, a practical one and effective solution was found.

If 0,5 1 e.g. is taken from the KORALLIN C 1500 in the hour, this was first guided over the substrate 600 times, at a filling height of 30 cm, this corresponds to a tube length of 180 meters during simple through-connection!

The high calciumhydrogencarbonate quantity resultant from this (30 - 40° KH) makes it possible to have to only take little water from the pile since it yes also has inside a pH value of 6,8. 30 drops in the minute already normally satisfy here in order to achieve the desired effect.

However, one should ensure without fail during constructive design, that surplus carbonic acid is not simple brought out (this is designated as "automatic ventilation" often). Already 10 bubbles in the minute too much sum up for itself in the course of one day to the impressive amount of 14.400 bubbles! This gas quantity then dropped from the device as the taken water and how can place a bell onto the tank for itself, there more heavily than air. I am secure, that many problems, which ones the calcium reactor principle as such ascribed will result (thread alga growth etc.), arise from incorrect service or deficient safety device at the reactor.

On the one hand, this can be the free with delivered CO2, on the other hand a too short machining time, it means a too small .hardening.

Only if the hobbyist learned the service with the device of his choice, an attitude should be chosen, that should be chosen with which one (only very small crowd) surplus carbon dioxide is brought out (this should only very much be few ones bubbles/day).

One must itself be in clarity, that yes only for the filling up quantity (= identical. running out quantity) required CO2 is in order to saturate this. This is during 30 water drops under 10 bubbles (at size of these drops).

It for logical reasons should run a calcium reactor 24 H since he would have to otherwise twice achieve at only day running so much. During run around the clock, the requisition quantity can be halved virtually unlike day running and consequently, contains less free carbonic acid.

The CO2 quantity of a calcium reactor should never be controlled in the form that the pH value of the tank is causal for the extra into the reactor. This order can only act as a safety shutdown circuit, there the pH value of the tank (and/or its CO2 requirement for saturation to pH 6,8) has nothing with the tank value commonly. A control would be able to lead reactor water only, that means pH 6,8 CO2 turn off, pH 6,9 may turn on. However, this method offers not advantage compared to the optical control (blistering at bubble in the reactor). Furthermore, one requires a very precise instrument (where the gauging accuracy is decisive, not scale accuracy!) for the electrode for this with regular maintenance requirements.

If a phosphate entry is feared by the small quantity of organic cloths included in the coral skeleton, this can be avoided by previous cleaning the employed coral sand easily at 5% of soda lye ("insert" approx. 24 H).

Experiments showed that the service of a calcium reactor can be increased if the substrate ""vibrates"and/or"shakes"". A principle as the rotating drum of a washing machine would be ideal here. However, that would increase the manufacturing costs considerably and would only be only at large tanks with immense consumption necessary.

One of the decisive advantages of a CO2 calcium reactor in opinion lie in its simple and low-maintenance working. Too without knowledge of the closer chemical connections (which methods other in the case of previously mentioned ones are positioned), can the hobbyist a sufficient calcium - guarantee supply to its small reef. This allows not only a small group of "freaks" the care of many limeconsuming invertebrates and consequently it is a contribution to preservation the natural reefs since successful care and increase in the sea water tank reduces the withdrawals to a minimum from nature.