Many hobbyists often wonder, why are water changes so important to fish keeping, we all regularly water change (hopefully) but what are all the benefits to water changing? What can happen if we don’t water change? In this guide we aim to explain this.
The first thing to remember is that in our tanks is a very small eco system. In such small environments things can quickly go wrong.
Nitrates
When a tank is stocked with fish and those fish create waste if your filtration is doing its job this will lead to an increase in Nitrates in the water column (Ammonia>>Nitrite>>Nitrate). Nitrates should be treated the same as Ammonia & Nitrite in that it is a toxin. Although the accepted level of Nitrate found in an aquarium is often higher, it can still poison fish and needs to be kept under control.
Water changes will reduce Nitrates for example let’s assume your replacement water (you are refilling the tank with) is 0ppm Nitrate. Your tank before a water change reads 40ppm Nitrate. By water changing 50% you would reduce the Nitrate levels to 20ppm.
Redox
Most people have no idea what this is. It’s one of the biggest promoters of immune and health and really it’s all down to having quality water with lots of good water changes. Fresh water has some of the biggest healing powers and preventions for disease.
Redox also known as Redox Potential, oxidation potential ORP oxidation reduction potential describes the ability for the loss of an electron by a molecule, atom or ion to the gain of an electron by another molecule atom or ion. Without this ability to gain electrons, many minerals cannot be absorbed and properly assimilated. So it is very important to keep a healthy Redox Balance via proper dissolved oxygen level, proper positively charged mineral levels such as Calcium and Magnesium.
As time passes without water changes there are several things that have a negative effect on Redox Potential. Fish excrete hormones into the water, these try to manipulate the fishes metabolism as well as growth factors and chemical reactions that control health and immune systems.
In summary Water Changes will help promote healthy fish and prevent many common issues.
Dissolved Organic Compounds
Water changes will remove dissolved organic compounds and toxins that can get into the water via air travel into the surface. These can contribute towards ‘old tank syndrome’.
Risk Of pH Crash
Over time GH will increase as this group of ions does not dissolve without water changes they will become more concentrated. Nitrate is acidic and will use up KH in the aquarium leaving the pH vulnerable to swings. pH crashes are extremely dangerous in an aquarium as fish can be very sensitive to this. When your pH drops your beneficial bacteria in the filter becomes less effective and can even die completely.
Increased Risk of Bacterial Issues
In bad water quality bacterial issues thrive such as Mycobacterium, Saprolegnia, Flavobacterium, and many other horrible issues. Water changes, will help prevent these issues arising.
Summary
For all these reasons water changes are crucial to a happy and healthy tank. As for how much you should water change and how often, it greatly depends on the fish you keep but essentially the more frequently you’re changing your water the better.