One of the best things that we can do to assure continuing success with our captive marine systems is to perform regular water changes. So very simple, yet so amazingly beneficial! Water changes achieve several valuable things, including the dilution of dissolved organic wastes, nutrient export, and replenishment of trace elements, just to name a few. When performed on a regular basis, water changes provide the inhabitants of the closed marine system a stable, consistent environment. And, environmental stability is one of the keys to success in our hobby!

Water changes tend to be viewed by most hobbyists as a necessary evil; a practice that we begrudgingly embrace to achieve a modicum of success with our aquariums. Many hobbyists will do the occasional 10%-25% water change once a month, once every couple of months, or even less often (oh, the horror!)! There is, however, a better way!

5% Twice A Week. That’s All I Ask!

As I just asserted, one of the primary benefits of the water change in a closed system is the dissolution of dissolved organics in the water. In the closed system, fish wastes and other organics are broken down by the beneficial bacteria that reside in the sand bed, live rock, and filter media. However, over time, the end products of the biological filtration process (nitrate and phosphate, in particular) tend to accumulate in the system. The accumulation of these products can lead to significant degradation of your tank’s water quality, and a reduction in the pH of the tank water. The key to eliminating this problem is, of course, regular water changes! If done consistently, regular small water changes can help dilute organic wastes before they ever have an opportunity to accumulate in your system. Trace elements will be replenished with fantastic regularity. Think of the money that you’ll save by not having to purchase all of those additives you’ve been using!

“Ok“, I can hear you saying, “I get the picture…Regular water changes are a good idea. But how much do I have to change…And how often?” Less than you think…but more often than you’d assume! My recommendation for an easy-to-accomplish, highly beneficial water change regimen is to perform two 5% water changes per week. “Twice a week! What a pain! Is this guy nuts?” Well, yes, but that’s another topic for another time! Seriously, though, this is a lot easier to accomplish than you might think.  

Think about it. Five percent of your tank volume (that’s only 5 gallons in a 100 gallon tank, or just 2.5 gallons in a 50 gallon tank), performed on, say, Wednesday and Sunday. By following this routine, you’re aquarium’s inhabitants are never more than 3 days from the next water change…and that is some serious frequency, my friends! However, this is not a daunting task, by any means. In fact, you can perform an efficient water change in as little as 10 minutes (Trust me here- I timed it!) . Using decidedly “low tech” methods, you can create a healthy, stable environment in your aquarium. When I say “low tech”- I mean it! We’re talking a flexible

plastic hose, nothing more! Sure, you could use one of those fancy store-bought numbers, but the tubing works just fine for me!

Obviously, when conducting the water change, you need to be sure to utilize high quality source water (such as RO/DI water), a good salt mix, and similar specific gravity, temperature, and pH. Environmental consistency is extremely important, and conducting water changes in a manner that breeds consistency will assure stability in your aquarium! Another side benefit of frequent small water changes is that you are “involved” with your tank on a rather “intimate” level, on a very regular basis. You’ll see what’s really going on in your tank, notice changes or sudden problems, and be able to correct them in a rapid manner. You’ll save money on additives, too! Rather than spend tons of cash on lots of different trace elements, additives, and assorted vitamin products, you’ll be able to replenish the majority of these compounds through these frequent water changes. Sure, you may need to supplement calcium, iodine, and possibly, a few other compounds which your animals utilize on a daily basis, but you’ll use far less of them in many cases.

And, while you’re making these regular water changes, why not use the opportunity to empty the collection cup and clean the neck of your protein skimmer (you do use one, right?), replace chemical filtration media , and clean mechanical filter pads and/or filter “socks”? By cleaning the mechanical media within your system often, you’ll help prevent detritus and organics from building up within them, which can measurably degrade water quality if left unattended.

Most amazing of all will be the noticeable results in your aquarium: Fishes will display brighter colors, eat better, and be more alert and active than you’ve ever seen them! Corals and invertebrates will display significant improvement in color, growth, and recovery following imposed propagation techniques. You’ll enjoy a whole new dimension of success with your system. Water parameters will remain more stable, nuisance algae will begin to disappear from your system, and your tank will take on a visual clarity that will astound you! All in all, your system will benefit enormously from the employment of these frequent, small water changes. Give them a try, and watch your system thrive as never before!