Here’s an example – say you have a 30 gallon tank and your sea salt manufacturer recommends 1.5 pounds of sea salt per 5 gallons of water to reach a salinity of 1.022. The math is 30 gallons divided by 5 gallons times 1.5 pounds of sea salts. This equals 6 times 1.5 or 9 pounds of sea salts. Now in reality, you’re not going to need a full 30 gallons of water because the live rock and coral substrate and other things in the tank will displace some of the water, so start with less than the amount calculated. In this case say 7 pounds of salt. Let’s makes two buckets full of saltwater, so add 3.5 pounds of sea salts to the water already in the 5 gallon bucket. You can mix it by hand stirring with a clean piece of PVC pipe or you can also add a powerhead or small pump to the bucket to mix the water. Once the water is clear, pour it into the tank and repeat the procedure. In the meantime, if your tank has deadrock (versus liverock) you can add say 10 gallons of freshwater to the tank. Once the first 5-gallon bucket of saltwater is mixed, pour it into the tank and mix well. Now make a second bucket like the first one, add it to the tank and mix well. Now you have about 20 gallons of water in your tank that should be at least 80% full, if not more. Get the filter and pumps running and fill the tank with freshwater to the final level you want, and then let the water mix for an hour or so. Next, measure the salinity. If the water is too salty, you need to remove tank water and add more freshwater. If the salinity is too low, remove 5 gallons of tank water into the 5 gallon bucket and add some sea salts. How much sea salt to add depends on your individual situation; you just have to estimate and re-measure. But remember there is no one absolute correct salinity value – you’re trying to get into a range. For most saltwater and reef aquaria at 76 to 80 deg F, the range is 1.020 to 1.024 on your hydrometer. Don’t fret about getting it exact – there is no exact!
Adding Salt to a Freshwater Aquarium | Random Bits of Projects
The article also makes mention of the inability to judge any consequences of using salt on freshwater fish. To say you use it and it has no side effects is like saying you smoke but you don't have cancer. How do you know you won't have it ten or twenty years from now? And similarly, how do you know the salt did not have some internal effect on the fish that may cause problems later? You don't, and neither do I. My approach is not to inflict the fish in my aquaria with something that is not in their natural habitat unless it is absolutely essential. That seems the safest route to follow, and the authorities cited in the linked article, as with those I have previously read, are not in disagreement.
Adding Marine Aquarium Salt To Freshwater Aquarium
There are two types of salt on sale: freshwater aquarium salt and marine aquarium salt. Freshwater aquarium salt is sometimes called tonic salt or livebearer salt. Some brands are little more than plain sodium chloride but some contain small amounts of other mineral salts as well that help to buffer against pH changes. Freshwater salt is usually sold in small boxes and the required dosage is normally estimated in very approximate terms, typically one or more teaspoons per gallon.
Aquarium Salt Mix: Salt for Saltwater and Freshwater Fish Aquariums