I'm going to be honest about water changes. In the 5 months I had my 20 gallon set up, I only changed the water about once a month and it was only about 3 gallons at a time. You will hear that you should change more but by the time you add substrate and live rock you usually have less than 20 gallons of water in your tank. :wink:
My best suggestion is this. Try to invest in a few more test kits. Nitrite, Calcium, and Phosphate are important. Every tank has different filtration capacity and feeding schedules. I'm not sure how often you'll need to change the water but you should be able to know exactly how often by the results of the tests. (The instructions usually tell you what the dangerous result ranges are.) If I got a result of Nitrate that was the level below dangerous, I did a 15% water change. If you are constantly changing water you're not allowing your tank to accumulate the beneficial bacteria that will eventually do the job for you. (Others may disagree here so I will say "what works for one doesn't always work for another".)
One reason people change their water so often is to replace calcium and trace elements that are found in most salt mixes. I personally dose my tank every other day with B-Ionic. First part is a buffer and second is calcium. It also includes the necessary trace elements. Due to this dosing the only things I really have to test for now are Ammonia or Nitrate. I don't know about you but I used to enjoy constantly testing the water quality in my tank when it was first set up. You kinda get a feel for your tank's "water quality behavior" if you are keeping a hawk eye on it for the first couple of months.
There are many discussions on this website that are helpful when setting up a new tank. Whatever you do please take your time and make sure you research enough to find the way that works best for you. At this point your rock should be fine with 1.026 range of salinity. Keeping corals, inverts, or fish is something that should be done very carefully. And please... whatever you do, don't listen to pet store employees (or owners) that tell you it's fine to add fish and corals immediately. They are more than happy to sell you more livestock when the first ones die.
(I actually made a Petco employee mad by interrupting him while he was telling a girl she should buy a 10 gallon tank, regular gravel and some clownfish and set everything up that day. She thought I was nuts when I told her the importance of waiting at least a month for bacteria to cycle but ya know what? She didn't buy anything from that store that day.)
Ok, I don't think we can write books here so I'll stop now but feel free to ask questions. That's what we're all here for. :lol:
