Calculate Salt amount for ick - based on aquarium labeled capacity or exact water volume?

[Kramer]

Hi all, I'm a new Oscar owner and just registered on this forum. Recently I noticed there're some white spots on his fins and he sometimes flashes his head against the gravel substrate. I was looking up online and believe that he's got ick, so I added salt according to this article: https://www.aquariumcoop.com/blogs/aquarium/aquarium-salt-for-sick-fish

Quick question is: do you calculate the salt based on the labeled capacity of your tank or the exact volume of water? Mine is a 55 Gallon, but if I do measure the length and width of the tank and minus the glass thickness, and measure the water height, the volume of water is actually much smaller. Even filled to the lower edge of the top black rim, I calculated that will be just 46 gallons. And if it's the exact volume, you still need to exclude the volume of the substrate, any decorations, etc... So just wanted to see how you guys do it. Your sharing is much appreciated!

[xXInkedPhoenixX]

Hi Kramer! Welcome to the forum, I'm sorry your Oscar is sick, that sucks. I'll be honest I've always just dosed according to the size of my aquarium (10g = 10g - this goes for all meds) and I've never really had an issue.  I'm also very guilty of eyeballing a redose when changing water (we do have to remember that the salt does not evaporate or get filtered out). Ich is a nasty one so personally I would not be afraid to dose per the tank volume (minus the contents) BUT if you've done all the calculations it would not at all hurt to dose for the 46 gallons and it should have the same effect! 

[Flumpweesel]

I dose to the actual water volume. So I measure from the top of the substrate to the water line  for the depth and recalc from there. I knock off a bit for ornaments as well but you'll just have to that by guesstermation.  (Is that rock more or less than a pint) but  only worry about that if you have very large pieces in there. 

My main tank is 220 litres as sold volume and I generally treat it as being 200 litres. It's a community tank so where some fish could probably handle the slightly higher concentrations some smaller or scaleless ones might struggle.

[AllFishNoBrakes]

I’ve always dosed on the labeled size. I’ve beaten ich a couple of times with salt. It has worked better for me than ich-x or anything else. 1 Tablespoon per 2 gallons (5 Tablespoons salt in a 10 gallon aquarium) has done me well in the past. 
 

The only other thing I will add is that it’s easier to add salt than it it to take away. As mentioned above, salt is only removed via water changes.