I will answer the "Why" first to prevent the question from taking over the thread. I sell saltwater minnows for bait, and I go through a fairly large volume of water (~300 gallons/week). Hauling water from the ocean is a real PITA, buying salt for $0.25+/gallon is not econmically viable.
Next I need to state that I would NOT reccomend "making a salt mix" for your prized pets without careful considerations to the potential problems you might encounter. For most this is a hobby and the cost of salt is fairly trivial.
With all the propper disclaimers in place, I am interested to know if anyone has any experience in mixing readily available commercial grade chemicals to form a reasonable facsimile to sea water. Following are the major components in sea water from a few referenced sources:
FORMULAE FOR ARTIFICIAL SEA WATER (Cl = 19.00 ‰)
McClendon et al (1917) Brujewicz (Subow, 1931) Lyman and Fleming (1940)
Salt g/kg Salt g/kg Salt g/kg
NaCl 26.726 NaCl 26.518 NaCl 23.476
MgCl2 2.260 MgCl2 2.447 MgCl2 4.981
MgSO4 3.248 MgSO4 3.305 Na2SO4 3.917
CaCl2 1.153 CaCl2 1.141 CaCl2 1.102
KCl 0.721 KCl 0.725 KCl 0.664
NaHCO3 0.198 NaHCO3 0.202 NaHCO3 0.192
NaBr 0.058 NaBr 0.083 KBr 0.096
H3BO3 0.058 H3BO3 0.026
Na2SiO3 0.0024 SrCl2 0.024
Na2Si4O9 0.0015 NaF 0.003
Obviously NaCl (common salt) is readily available. Locally a 40# bag is < $4.00 ( <$0.10/#)
MgCl2 (Magnesium Chloride) is used industrially and commercially as a road de-icer and dust inhibitor. I do not have any pricing information on this item yet; however, it should not be more than an order of magnitude higher than NaCl, so it should be << $1/#
MgSO4 (Epsom Salt
) is readily availabe in most grocery stores and drug stores and is < $1/#.
CaCl2 (Calcium Chloride) is used industrially and commercially as a road de-icer and dust inhibitor. Again, I do not have any pricing data on this; however, it should be <<$1#.
KCl (Potassium Chloride) is marketed as a water softner alternative and runs <$10/40# bag.
NaHO3 (Sodium Bicarbinate...Baking Soda) is readily available and considering the extremely small quantity required is very cheap <$1/#.
Assuming that Salt = $0.10/# and Potassium Chloride = $0.25/# and thar all the other chemicals are $1/#, this would bring the price of "fake" sea salt to ~$8.11/100 gallons of water. If the "other" chemicals are only $0.50/#, then our cost would drop to ~$5.25/100 gallons. Obviously if you are maintaining 'pets' this savings is trivial; however, as previously stated, in my case this potential savings is worth exploring.
My question would be if anyone has 'played' with "making a salt mix", and if so, would you share any results and/or observations about the importance of the presence of the various chemicals. Please remember that I have no interest in the long-term health of the fish, my main objective is to reduce mortality. Currently I loose 6-12 minnows a day using nothing but pure NaCl; however, improving on this mortality rate is an effort to maximize profits with the added bonus of improving the health of the remaining stock.
Information that would be helpful would be any trial and error efforts to improve health by the addition of one or more of the 'trace elements' to otherwise stable aquariums. For instance, if anyone has experimented with elevating KCl from .7gm/litre to say .8gm/litre and noticed any positive OR negative affects, this would be very useful information.
While any and all input is welcome, please refrain from reccomendations of various 'name brand' mixes unless you happen to know of a source for purchasing them for <$0.08/gallon or $4.00/50gal; my target cost/gallon needs to be in the $0.03 to $0.06/gal range with the 'break-even point' being ~$0.07/gal.
It is my hope that the discussions in this thread may help others to experiment with adding trace elements to their existing mixes to improve the health of their pets.