Quote:
Originally Posted by
wayner 
I lift it to the top of the tank and glimps underneith, but its never out of water. Wouldent a garbage can be to much of a water change for the shark and fish? Second opinions welcomed

Glad to hear you are feeling better...
It all depends on if you have problems. Whatever you use, make sure it have never been used before...mark it FISH ONLY and never use it for anything else. This is VERY IMPORTANT to do.
Alright you have a 75g tank. If you are still having a cloudy water issue or any kind of problem at least change 3%, that's 25g...Ammonia spike change 50% That's around 37g
If you are doing weekly water changes and nothing is off, 10g
If you are doing monthly water changes and nothing is off, 25g
Look at it this way, the largest water change you need to ever do would be the 37g so it makes sense to purchase a plastic tub or garbage can that can hold that amount of water. You don't have to fill it each time you do a change, but you want to be able to do a big one if you need to. Mixing up the salt water can be a pain if you have to do it in 5g buckets. One big tub or can and keep track of how much water you have put in will give you a ball park of how much salt to add. Then check the SG after it has cleared so it is totally dissolved. Match it to your tanks SG, If you need more salt add 1/2 cup at a time, if the SG is too high add a little RO water.
A good power head to get is the Petco one, they have a large one and a small one, get the large one it costs $19.99 and it works great for water changes. It churns the water real good and is powerful enough to pump the water up a hose and into your tank, making water changes easy.
For you tank you want two Koralias, One Number 3 and one number 2 would work really well in a 75g. maxi jets are cheaper and two medium sized ones will work fine, they are a pain to get to stay where you want. They use suction cups and the vibration from the power head makes it come lose. Koralias have a magnet and they stay put, as well as being on a swivel to aim them any direction, they are worth the money.