Properly prepared water in the quantity you’ll need to replace or water conditioner to treat chlorinated tap water. An algae scraper for cleaning the glass inside the tank (scrubby pad, straightedge, or combination). A 5 US gal (19 L) bucket dedicated for this purpose. A simple siphon-type gravel vacuum (NOT a battery-operated gadget). Filter media (cartridges, sponges, carbon packets, and so on) if you’re changing the filter this time. Aquarium-safe glass cleaner or a vinegar-based solution. 1⁄4 cup (59 mL) of bleach per 3–4 US gal (11–15 l) of water in a separate container (optional). Metal or plastic razor blade (optional, be careful with acrylic tanks, as these scratch easier).
You might want to wear aquarium gloves to complete this job, especially if you are allergic to anything in the tank (like a synthetic salt mix). Choose shoulder-length plastic gloves designed for use in aquariums. Do not just use the sponge or scrubber from your kitchen sink or anything that could have the residue of detergent or cleaning chemicals. A clean, tank-only algae pad will prevent harsh chemicals and detergents from getting into your tank. A magnetic glass cleaner is better to clean fish tank glass without wet hands. This step can also be done after you take out 10-20% of the water.
If your goal is to reduce nitrate and phosphate to minimum levels, large, more frequent water changes are required. And, if you do larger water changes (50% or more), you can perform them less often. Note that a weekly 10% water change is inferior to a 40% change once per month.
Aquarium siphons can be purchased that hook up to a sink. If you have one of these, read over the instructions on how they work. This type of siphon also prevents water spilling from the bucket. You can use the same hose to siphon and fill the tank. Use a hose with a small diameter if you want a gentler flow of water.
Clean at least 25-30% of the gravel each month. If you have sand substrate, lower the flow rate by putting your finger over the end of the siphon or kinking the hose. Hold the hose 1 inch (2. 5 cm) or less from the surface and use it suck up waste without disturbing your sand. Run your fingers through or stir the sand (provided there are no buried animals to disturb) to help release gunk trapped underneath it and prevent the formation of anaerobic zones.
If you’re having difficulty cleaning the decorations, remove them from the tank and soak the items in a large bucket filled with water and 1⁄4 cup (59 mL) of bleach for 15 minutes. Rinse the items thoroughly and treat them with chlorine water conditioner. If they are porous, let them dry completely before returning them to the tank. If you’re having algae issues, lowering the nutrient accumulation or exposure to light will help. You can close your window coverings, move the tank away from a window, or adjust the lighting schedule. Alternatively, perform larger or more frequent water changes. Having a true flying fox, otocinclus, or rubber nose pleco in larger tanks can prevent algae from growing excessively.
Avoid overfilling the tank. If you use tap or faucet water, conditioning the water to remove chlorine, heavy metals, and other toxins that your fish can’t process is a must. Choose a conditioner with an ammonia detoxifier chemical. Plan ahead and fill a bucket the day before you perform the water change. Add the water conditioner and allow the water to sit overnight. Make sure that the water you refill the tank with is the same temperature as the water in the aquarium—a difference of more than 1 °F (−17 °C) is very dangerous for your fish. If the nitrates are astronomically high, you can do a water change with reverse osmosis water from your local fish store. Add a freshwater aquarium buffer to the water to keep your tank stable.
If you have an acrylic tank, you can buy a special polish for it.
Place the water in a clean plastic bucket, preferably used only for this purpose. Heat the water with a specialized heater, purchased at a pet store. Add the salt mix. One-step salt mixes are available at pet stores. Follow the instructions on how much to add based on how much water you are using. The rule of thumb is 1/2 cup of mix for every 1 gallon of water. Aerate the water while mixing in the salt. In the morning, check the salinity with a refractometer, hygrometer, or salinity probe. In fish-only systems, you can shoot for a salinity of 30 grams per liter (g/L) as a baseline. In some cases, such as if you have corals in your tank, you may need to mix the salt to seawater concentration which is 35 g/L. Check the temperature with a thermometer. For saltwater fish, it should be between 73–82 °F (23–28 °C).
An algae pad for cleaning the glass inside the tank. A 5 US gal (19 L) bucket dedicated for this purpose. A simple siphon-type gravel vacuum (NOT a battery-operated gadget). Filter media (cartridges, sponges, carbon packets, and so on) if you’re changing the filter this time. Aquarium-safe glass cleaner or a vinegar-based solution. pH strips. A refractometer, hygrometer, or salinity probe. A thermometer. 10% bleach solution in a separate container (optional)
Lower the flow rate by putting your finger over the end of the siphon or kinking the hose if you have sand substrate. Hold the hose 1 inch (2. 5 cm) or less from the surface and use it suck up waste without disturbing the sand. Stir the sand to prevent the formation of anaerobic zones.
