Thanks for the welcome! Bruce wrote on RemoteCentral about your forum and I thought I would check it out.
IMO, doing routine waterchanges is one of the most critical steps you can take for maintaining a successful reef tank. A proper waterchange will both lower the amount of harmful nutrients, such as nitrates and phosphates, and replenish helpful trace nutrients that are used up by your corals and other livestock. I wish that it were as easy as hooking up a hose and turning on your faucet, but it ends up that it isn't too much harder. You basically have two choices when it comes to your mix water, you can buy it at your local fish store already made, which is convenient but can become expensive, or you can make your own. I prefer to make my own.
A successful water change starts with clean water. Although some people are fortunate enough to have that right out of the tap, most tapwater comes with significant amounts of sediment, phosphates, possibly heavy metals and chlorine (if using treated water). To get these out, you should run your tapwater though a set of filters including one or two sizes of sediment filters, an activated carbon filter, a reverse osmosis filter and finally a deinization filter. If you water provider uses chloramine instead of or in conjunction with chlorine, you will also need another filter for that. It is also helpful to have a pressure gauge and one or two TDS meters connected inline with the filters so that you know when they need to be changed out. Since this is such a common setup for aquariasts, there are several vendors who offer a kit with all of these filters, which runs between $100 and $200. If you run your water through the deionization filter, it is a good idea to aerate the water before going on to the next step.
Now that you have your clean water, it is time to add your salt (yes, you do need salt water for a saltwater aquarium and no, you shouldn't use table salt). Although many aquariasts and vendors will espouse the benefits of one salt brand over another, I think that most major brands of salt work just fine (there may be a parallel here with audio gear, but I'll leave that alone). But, how much salt do you need to add? Because we are trying to replicate most of the conditions of the ocean, the salinity of seawater is commonly used as the basis for your mix water. However, salinity is fairly hard to measure, but luckily, specific gravity can be used as a fair approximation. The specific gravity of sea water is 1.0264. There are several instrument commonly used to measure specific gravity including the swing arm hydrometer (cheap but commonly innaccurate), the floating glass hydrometer (more expensive, fragile and doesn't compensate for water temperature) and refractometers ($30-$50 and most compensate for temperature). I recommend using an ATC (automatic temperature compensating) refractometer.
Now it's time to do the water change, right? Not quite. Once the salt has been mixed, it is good to let the mix water "age" for at least a few hours, but better, for at least a day. When you add the salt mixture, it doesn't just dissolve in the water, it also undergoes some chemical reactions. Aging the mix water allows these to go to completion before it's added to your tank. After the mix water has been aged, it is also a good idea to bring the water up to your tank's temperature and to aerate it before doing a waterchange so that the shock to the inhabitants is minimized. Some people also measure and compensate for pH differences, but I've found that the pH difference is minimal if I've aerated the mix water.
How often do you do a water change? There are many theories and practices going around. Some people use an automated system to change their water on a continuous basis, the theory being that there is no shock to the inhabitants and that the trace elements are replaced as they are used. Others go for months without a water change or don't do any at all, saying that their tanks are running fine without them. I personally think that the people who can successfully keep an aquarium without waterchanges is very low and that those who go without would see a beneficial change to their aquarium if they started doing water changes. I do a weekly, roughly 10% waterchange. This is frequent enough that the trace elements are not fully depleted. It is large enough so that the waste products are removed (one 10% waterchange removes significantly more waste than ten 1% changes). Most importantly, it is infrequent enough that it doesn't become a burden.
Reading through this, it may sound like a time-consuming process to do water changes, but it really isn't. It takes me roughly 30 minutes, once a week, to clean my aquarium, clean my skimmer and do a water change. I make up mix water about once a month and it takes me about 15 minutes of actual work. Most of the rest of my aquarium is automated. Here is a picture of the area I have setup to mix my water and includes the filters, TDS meters, bulk water storage container (trash can), salt and 5-gallon containers for the mix water:
Here are some pictures of my aquarium:
Thanks!
CJ