Make sure that when you research any African Cichlid specific salts that you understand that
Magnesium Sulfate (
epsom salt) is completely different than Sodium Chloride (
aquarium salt).
You can use both at the same time.
I think that the salt that the OP is referring to is regular aquarium salt.
Dosing Epsom salt is going to depend on your dGH.
With your tanganyikans, you can dose 1 tablespoon per 5 gallons up to 1 tablespoon per 3 gallons of aquarium salt and they will be just fine.
Having said all of that...i usually only dose aquarium salt to clear up minor issues due to aggression...(occasional mouth fungus from lip locking etc) but still, using it wont hurt your fish.
The thought behind over using aquarium salt is that bacteria and
fungal infections in your tank can become tolerant to high
salinity making the salt less effective, therefore you should use it sparingly.
With Epsom salt....the more you add the higher your
general hardness will be. So if you shoot for a dGH of 10-18ish using a hardness
test kit....that will tell you how much Epsom salt to dose.
I redose Epsom salt with every
water change keeping my dGH around 15ish.
Oh....I keep Malawi cichlids btw.
Also.....man, sometimes fish just die and its not your fault. Alot of aquarium fish in the hobby just have bad genes.
If you think that there might be a problem in your tank, using aquarium salt as a preventative treatment is totally acceptable. And much preferred over preventative medications.
If you want to dose aquarium salt i would add it at a water change and run it for about a week.
Then don't redose it....just dilute it over time with water changes.