Regular water changes are a big part of fish keeping, both in ponds and aquariums. Often considered one of the drawbacks of fishkeeping, it is nevertheless essential in most cases. But at Swell UK, we’ve learnt there are a few tricks and toys that can make this task easier, cheaper and faster.

Why do we need to do water changes?

Not only are regular water changes a great way to keep your water fresher and topped up, but they are a great opportunity to check up on your water quality, perform tests and check your fish are happy and healthy.

Whether you are keeping a pond or an aquarium, the nitrogen cycle has to be taken into consideration too and is arguably the primary reason you need to do water changes, as well as removing some of the gunk and rubbish from the water.

Your fish obviously produce wastes – it’s a fact of life. In a closed ecosystem like an aquarium (and much like a pond too, although not quite as closed), this waste breaks down into ammonia, which is poisonous for fish in large quantities, burning their scales and skin, and inhibiting their breathing by damaging the gills. Not only that, but if phosphates are present too, combined with a high ammonia content, you’re looking at getting a large bloom of algae sooner rather than later.

Your pond filter plays a huge part in the fight against ammonia, turning it first into Nitrites (sadly, just as damaging as ammonia for your tank), and then quickly into Nitrates (much safer). This is where your water change comes in. When you are performing a water change you are also removing large quantities of nitrates from the water which will otherwise have no place to go apart from into plants (which you may not have).

You can see why it's important then – without water changes, your tank is going to get dirty, and full of nitrates, which will eventually become a problem once they are concentrated enough.

Tips for performing water changes in aquariums

Aquariums are where water changes are at their most important. In ponds, your plants will handle some of the nitrates, but in most freshwater and marine aquariums, they need to come out.

Use a gravel cleaner:

This is one of the best ways to do your water change, as you are killing two birds with one stone, cleaning your gravel and removing water at the same time.

Gravel cleaners range from inexpensive models such as a large plastic tube with a flexi-tube to draw the water through, either activated by syphon action using your mouth, or by a syphon starter motor or pump. As you manually probe the plastic cylinder part through the gravel substrate, you churn up a huge amount of dirt and debris that has made a home of your substrate. Sucked up through the syphon and deposited from the bucket, this is a great way to remove dirt and nitrates from your water.

Other options include using a circulation pump or other compact powerhead placed inside your tank, with a tube running for it, out to your waste bucket or drain, however this will not sort your gravel out at the same time, and the pump may become damaged by sucking up gravel.

Replacing the water

Of course, we are talking about a water change, not just a water reduction. Once you have removed the water from your tank (normal water changes usually remove around one 5th to one quarter of the tank’s capacity), you need to put something back.

The water you are adding to the tank needs to be dechlorinated first. While smaller tanks and changes can be readied with liquid or powder treatments, we find that plenty of customers save money in the long term by investing in an RO unit.

These machines use reverse osmosis to provide up to 150 gallons of pure H20 converted from tap water in a single day (depending on the model). Long-lasting, and with an increasable lifespan when you change the membrane, these units are quick, efficient and easy to use, and if you have a large tank that requires regular water changes, we recommend you invest if you can.

As we mentioned before, water changes are a great time to test your tank and revaluate your water quality. Using a reliable test kit at this point is the best way, and if you find that certain chemical factors in your tank are either lacking or exceeding their optimum parameters, now is a great time to ensure the new water you are adding is loaded up with just what the rest of your tank needs.

Check out the best marine salts and aquarium additives to achieve the best results.

That’s really all there is to it – check your water quality as you add and remove water, and try to sort as many problems out during your change rather than going back to them afterwards – easy!