Just in case for those who had not read the entire thread and try to do the math, here is from pages 3 and 5:
On supplementation I would say that at the end it almost becomes a matter of personal preference and convenience. Cost wise there seems to be what looks like a significant gap between using aquarium commercial products and using non aquarium products.
A) Two part supplements:
If you are into saving as much as you can, nothing will beat using non aquarium products like Ms Wages Kalk or DIY two (three) part solution using Magflake, Dow Flake and Baking Soda. Just note that although cost is a pro, there is a con in the form of increased risk and less convenience.
So far these product have proven reliable but not a single manufacturer is or will be willing to assure any quality control in those products and given the manufacturing process there is always a good chance of getting Ammonia in the flake products. Ms Wages has in occasion leaves some unidentified brownish residue.
Also; and this is true for all two parts, there seems to be, judging by the posts in the chemistry forum for a higher difficulty in maintaining stable levels and higher chance of over or under dosing.
Commercial aquarium two part supplements will reduce the risk of contamination but will increase the cost.
Finally two part supplements may affect the ionic balance between sodium, chloride and sulfate if used for a long time without proper water changes.
B) Kalk dripping:
This can be one of the cheapest ways of supplementing if using a simple drip jug using a food Kalk like Ms Wages.
Addition of a reactor, doser pump and top off plus timers will increase the initial investment.
Unfortunately Kalk addition has a limitation. As it replaces the evaporation, the maximum amount of calcium and alkalinity to be added is limited by the amount of daily evaporation in the tank (see chart below). In my experience, although Kalk can cope with the consumption of a lightly loaded or softies tank, I yet have not seen an sps loaded tank that do not require a second form of supplementation.
C) Calcium Reactor:
A properly set up reactor is by far the most convenient of the supplementation methods and the one that might have the highest capacity for addition.
Although on a per unit of alkalinity the reactor media is the cheapest of the supplements, the initial cost of the reactor and peripherals makes the overall system more expensive for small to medium size systems.
In addition to the initial cost, a calcium reactor usually will require more experience to achieve the proper set up and trouble free operation.
Which one to use??
There are basically two factors that affect the decision, convenience and cost.
convenience wise if addition every two or three days is not an issue and the system is relatively small (a nano) a two part commercial or DIY additive will be convenient (if not basically the only alternative), as the tank gets larger and consumption increase, preparing the supplements and having to dose daily can turn into an undesirable chore so automation starts to get into the picture which now starts increasing the cost of two part or kalk addition but increasing the convenience for the aquarist.
Cost wise there are two factors that define the overall operational cost, the size of the system and the daily consumption
Although precise definition of costs is extremely difficult given the different products, sources equipment and peripherals designs and their costs below there is a chart that shows the approximate average annual cost for different supplementation methods for a 55 gallon system. Again the break even points between the methods can swing significantly depending on specific media and equipment sources and the "fanciness" of the set ups.
Note that the least costly option will be to get some Ms Wages Kalk and drip a kalk mix using a basically zero cost plastic jug and an air hose (Green line). At about a consumption of 2 dKh per day the required evaporation (around 1.75% of tank volume) may start limiting the amount of supplementation that can be added. so in that case changing to the next less costly alternative, the manual addition of a DIY supplement, will be required (blue line).
Automating the addition of two part (Orange line) will increase it cost but not as high as what the cost would be by automating the lime addition using a Kalk reactor (Purple line). Note that Kalk could be automated without the use of a reactor (line not shown), the cost of this automation will be very similar if not cheaper than the automation of a two part dosing system so if not using a Kalk reactor, automating Kalk addition will be cheaper than automating two part addition.
In either of the Kalk cases at about 2 dKh of consumption another supplementation method shall be considered, in this case the automation of the two part addition.
Finally in this case cost wise a calcium reactor will be the most expensive alternative and if elected might be for the added convenience and why not a bit for the love of aquarium toys
So for a 55 gal system potentially dripping Kalk, manual addition or automating a DIY are good alternatives
Now if we increase the size of the system to say 120 gallons the comparison may look a bit different.
For a system this size automation is almost granted so no comparison is made with dripping Kalk or manual DIY additions but rather comparing automated Kalk reservoir, automated DIY two part, automated Kalk reactor and automated calcium reactor.
First thing to notice that a Randy style Kalk reservoir with a doser pump and top off will be the lowest cost alternative up to the level were evaporation does not allow for higher addition.
If there is no room for a Kalk reservoir the automating two part solution is the alternative but note that it become more expensive than a Kalk reactor at a consumption of only 0.9 dKh which is an unusually low consumption so in this case a Kalk reactor seems to be the logical alternative.
Finally if this is a heavy loaded system and the consumption exceed 2 dKh per day the alternative will be the calcium reactor.
So for a system this size with light to medium consumption automation of a Kalk reservoir or a Kalk reactor will be the alternative and for a heavy loaded system a properly sized calcium reactor is granted and will not be a luxury.
Calculating your cost
I see some posts trying to compare costs, for a proper comparison the initial setup cost shall be tied with the on going operational cost and media consumption.
I will suggest the following to approximate a cost comparison:
a) Determine your setup cost (do not forget to add shipping and handling)
b) Assuming your setup shall last at least five years determine the annual cost dividing a above by five
c) determine your alkalinity consumption
d) Use the chart below as a guideline to determine the annual ongoing cost of your supplementation system. (Calcium reactor include CO2 and Power). As the chart is for 120 gal. Divide the number by 120 and multiply it by the volume of your system.
e) Add the ongoing annual cost to the initial setup cost and compare.
f) Add to the equation whatever your feelings are regarding convenience, risk and such and make your move and enjoy your new toys!
I don't think I would go as far to call anyone here stupid...
