Brackish tank

[Columbian Shark Catfish]

So I'm taking my 75 gallon freshwater tank with 2 Columbian Shark Catfishes, and making it brackish, probably starting within the week. I have a couple questions, and if I could get as many answered, that would be great
Sorry if my salt water terms are bad, I've never done anything to do with saltwater.

1. Do I need anything beside Salt and the salinity measure thingy?
2. When I add the salt to the water in a bucket, I let it dissolve, then measure the salinity and keep adding more until it's the right amount?
3. Since water evaporates, some salt will stay in the tank, how do I know how much freshwater to use every water change?

If I have anymore questions, I'll post them, but this is all I can think of at 1 o'clock in the morning.

Thanks for whoever answers, I can't wait until it's set up!

 

[SalmonAfrica]

1) The thing you use to measure salt with is called a hydrometer - most stores should have them. Go for the plastic swinging-arm hydrometer, mainly because they don't break as easily. I'd also recommend getting a really good external filter for your Shark Cats because they like to eat and make a mess.

2) Pretty much. Make sure you can dissolve as much salt as possible before you measure. If their is a bit of excess salt at the bottom, it doesn't matter, because these guys can in fact benefit from random changes in salinity.

3) Rather don't add the freshwater during the water change. Add pure freshwater before the change, then do the change.

 

[Columbian Shark Catfish]

Ok thanks so much!
!!!!!

 

[jamesdecruz]

Youre filter will need to re-mature with brackish tolerant bacteria before you put any fish in youre tank.As for evaporation only water is lost and not salt so just mark water level and topup with fresh water,also do this before a water change as it helps keep a steady sg