water changes

[Jack]

1/2 a cup per gallon is a good mixing point. I do a 12 gallon water change every 2 weeks so I use 6 cups. It's easy.

Take the amount of gallons and divide by 2, that's how many cups of salt. So for your 20 gal change 10 cups should do it. Make sure your water is up to required temperature and it's well mixed before you check your SG.

Edited: (And I thought I was gonna be the first to post, man you guys type fast) So ya, what they said