Your aquarium inhabitants rely on you for everything. It should therefore be your #1 priority as an aquarium keeper to provide your wet pets with the best habitat possible. Keeping your tank parameters in check and your water clean is the best way to keep livestock healthy and prevent nuisance algae growth.

This article will cover the most common, most effective ways to maintain high quality water in your aquarium. While our focus will be reef environments, many of the recommendations below will also apply to saltwater fish-only and freshwater aquarium systems.

1. Biological Filtration

Without any biological filtration, your tank can quickly become a toxic cesspool of fish waste. A properly set up biological filter allows beneficial bacteria to breakdown fish waste to make your water safe for livestock. We recommend using high quality live rock as the biological backbone of a reef aquarium system. For fish-only and freshwater aquariums, you can use a wet/drycanisterfluidized sand or hang-on-back filter for biological filtration.

2. Mechanical Filtration

Mechanical filtration is another filtration method used to trap and remove detritus and debris from aquarium water. This removal can be accomplished using filter pads, sponges and/or filter socks. Mechanical filters are very effective at catching detritus, but they also have a tendency to become clogged, so be sure to replace or clean your pads/sponges/socks regularly. Protein skimmers are another type of mechanical filter for saltwater aquariums that many hobbyists regard as an essential part of a properly set up reef aquarium filtration system.

3. Chemical Filtration

Chemical filtration is used to remove dissolved organics from aquarium water. This can be the removal of nitrate, phosphate (high phosphate can inhibit coral growth and fuels algae) or tannins (usually seen in yellowing water). Filter media like carbon (eliminates organic pollutants, odors and discolorations), granular ferric oxide and resins are used to absorb or adsorb pollutants and will help improve water clarity as well.

4. Refugiums

refugium is an area or refuge where micro-organisms can live and breed without the worry of predation from fish or other organisms. Macro-algaes are also kept in refugiums to aid in waste (nitrate and phosphate) removal from the aquarium’s water. Many people set up refugiums as part of the filtration system for their saltwater aquarium, especially with reef tanks, where nutrient control is a huge concern.

5. BioPellets

When used in combination with a media reactor and quality protein skimmer, biopellets will reduce nitrate and phosphate levels in aquarium water. Due to the increase in popularity of biopellets as well as other probiotic and labile organic carbon dosing methods, we’ve brought aboard an expert to answer your questions in a public setting to benefit all hobbyists searching for information on these subjects.

6. Additives & Supplements

Many different types of additives and supplements can aide in improving aquarium water quality. AZ-NO3, for example, uses your protein skimmer to help export nitrates from water. PO4 Minus works in a similar fashion and, when used as directed, will reduce phosphate levels in your aquarium. Using probiotic and labile carbon dosing additives, like Prodibio and Zeovit, can also help maintain pristine water conditions in your tank.

7. Reverse Osmosis (RO) & Reverse Osmosis/Deionization (RO/DI)

We’ve said it before and we’ll say it again: RO and RO/DI systems may be the most overlooked pieces of equipment that will help you really succeed in the aquarium hobby. Using high-quality water from the outset can make all the difference in the world. RO and RO/DI filters remove impurities from tap water like chlorine, chloramines, pesticides, phosphates, heavy metals and many others. These impurities contribute to the growth of nuisance algae, while others can cause even larger problems. Not only should you be using RO or RO/DI water for mixing saltwater, you should also use it as top-off water for your aquarium to replenish the water lost from evaporation.

8. Water Changes

The best way to keep your aquarium water clean is to perform regular water changes. Water changes are, wholly or partially, the solution to most water quality issues in aquariums. The amount of water you should change depends on the size and bioload of your aquarium. Some of our staff prefer to change 5-10% of the total tank volume every 1-2 weeks, while others opt for larger, less frequent changes such as 20-25% every 2-4 weeks. In general, smaller tanks (pico and nano size) and/or aquariums that have a higher bioload require more frequent water changes.

Without a properly built and regularly maintained filtration system, your aquarium’s water quality will slowly degrade to the point it becomes unhealthy for the livestock living inside the tank. Poor water quality can also lead to other issues, like problematic algae growth. If you are considering improving your aquarium’s filtration system or would like help choosing components for a future tank build, please contact us for advice or to bounce ideas off. We’d love to hear from you!