1/4 cup per gallon... per mix it in a 5gallon bucket, as for drcore you can go with anything, soak the drift wood in water and change the water often, boiling it also helps to get the tannons out, thats what makes the water a tea colored, your normaly looking for a ph of about 7.5-8.2 so the wook font help but it wont hurt either., coral looks good, and if your going with puffers then it gives them something to knawe at. instant ocean is a good salt and you can get a bucket to last for a good while, just remember if the water evaporates the salt concentrates and should not be topped up with salt water. i would definetly invest in a good salt, with the instant ocean it adds minerals as well as salt and some think its the best salt out there.