As a dedicated aquarist you want to keep your aquarium looking great with healthy fish, plants, corals and other aquatic species you’re keeping. If you’re like me, I’m always on the look-out for the latest lighting system, water pump or supplement to keep my tank in top shape. But the best gear and latest additives won’t benefit your aquarium unless you’ve got good water quality. Below are 6 time-tested steps to improve the water quality in any aquarium. All are easy and guaranteed to work!

Start with Purified Water

Reverse osmosis systems to help purify water

The water you add to your tank can make keeping an aquarium easy or very difficult; here’s why. Even though your tap water meets drinking water standards it doesn’t mean it’s suitable for the aquarium. Many tap water supplies contain copper and other heavy metals. These metals leach into the water from underground pipes and your own plumbing system - aquatic life is very sensitive to metals.  Water treatment plants add phosphate and silicate-based corrosion inhibitors to protect the pipes, if used, every water change and top-off would add these algae-promoting nutrients to your tank. Having a reverse osmosis deionization (RODI) filtration system will remove these substances along with chlorine, chloramine, nitrate, nitrite and other undesirable substances from the water supply.

Marine salts formulations are based on using pure water. RODI water allows the salts to dissolve cleanly, creating the right ratio of salts, minerals and trace elements.

For freshwater RO filtration systems are recommended . Hard water makes it difficult to keep live plants. Lowering the pH is almost impossible with high alkalinity. RO water makes fine-tuning your freshwater aquarium easy. With RO water, every top-off helps to stabilize the water chemistry, not throw it off by adding pollutants and excess minerals and nutrients.

Don’t Over-feed the Aquarium

While there’s no one-size-fits-all rule for feeding your aquatic life, one thing is always true: the more food you add, the greater the waste load on the tank’s ecosystem. Food consumed by fish, coral, and other invertebrates are only partially digested and excreted as waste products into the water. Uneaten foods break down, releasing nutrients, organics and solid particles into the water. You may also see a spike in toxic ammonia or nitrite if you feed more than your biological filter can handle. Phosphate and nitrate may become unmanageable. There’s a natural tendency to feed too much. We want to be sure our fish and inverts get the nutrition they need. But over-feeding will reduce water quality, which always leads to disease and algae problems. Not overfeeding our tanks is one of the easiest steps to improve water quality.

Swap Out your Mechanical Filter Media

Most aquarists don’t service their filter system often enough. Mechanical filters like sponges, filter pads and filter socks are designed to capture and remove suspended particles from the water. But what happens if you don’t change or rinse your mechanical media? The organic debris decomposes, releasing dissolved organics and nutrients back into the aquarium. The idea is to remove the debris from the aquarium before it decays. If you want to have clear water and less algae, clean those filter socks and other media every week. If touching dirty filter socks isn't your thing, then there is the option of installing a filter rolling system that automatically rolls up dirty filter and exposing a new filter portion.

Change Chemical Filter Media

Assorted chemical media to improve water quality

Chemical filtration media like activated carbon, phosphate remover and other specialty media remove pollutions by adsorbing them onto the surface and within microscopic pores. It only takes a few weeks for bacteria and other microbes to coat the surface of the media. This blocks adsorption sites and reduces the effectiveness of the media. Granular filter media can act like a mechanical filter, trapping particles of organic matter. If you’re using a contactor or reactor, flush the system every few weeks if you see debris clogging the media. Replace bagged filter media at least once a month for maximum effectiveness.

Test the Water

Hanna Instruments

Reef aquarists know the importance of monitoring key parameters like alkalinity, calcium and other elements necessary for keeping corals in captivity. But many marine and freshwater aquarists stop testing until a problem arises in their tank. In most cases the problem could have been avoided by monitoring water quality with test kits. Be alert of trends that indicate a decline in water quality and act quickly to correct the problem. If testing shows everything is fine, keep that stability in your tank and make it a part of your tank scheduled duties.

Make Water Changes

Another of the simplest and most effective ways out of the 6 steps to improve water quality is through partial water changes. Water changes provide several important aquarium maintenance jobs at one time. Changing water reduces algae-promoting nutrients like phosphate and nitrate, making it harder for algae to grow.  A build-up of dissolved organics suppresses your aquatic life’s immune system. Water changes remove both particulate organic matter and dissolved organics. Dissolved organics also absorb some of the light energy that should be reaching your corals and plants. If you’ve got a reef tank, water changes with a high-quality marine salt will restore the elemental balance. pH-balancing carbonates are replaced as well as calcium and magnesium.

Infographic of tips to improve water quality in the aquarium

Final thoughts

You’ve probably heard about many of these simple steps to improving water quality. But are you consistently servicing your filter, feeding properly and changing water? Follow these steps and you’ll see a dramatic improvement in your tank!