When to Water Change an Aquarium: Explained
- Aug 01, 2021
- Anshika Mishra
- 411 0 0
When to change the water in your aquarium? The answers are much simple than you might think. The simple, non-complicated answer is that you should water change your aquarium anytime you reach about 40ppm, give or take a few.
So, why is that so simple? If you understand the Nitrogen Cycle, you must understand that nitrates are the final steps into the cycle and are very harmful to our fish. So, we, as fishkeepers, are supposed to remove those nitrates by water change.
High-Nitrate Levels
Many factors determine how fast your Nitrate-levels rise, and that is where it depends things come from because it does depend on many many factors, including but not limited to:
- Tanks size
- Fish size
- Fish species
- Number of fishes in the tank
- Cleaning schedule
- Feeding
- Type of food you feed your fish
- Quality of food
- Feeding frequency
- Vacuum Schedule
- Live plants
- Filter efficiency
Yes, all of the above things decide how quickly the nitrate level in your tank rises. But the bottom line for your tank is when your nitrate level goes above or near 40ppm, whether you get there in one week or before. For the tanks with frequent nitrate spikes, try doing about 80% of the water change.
We say 40ppm because that is the consensus in the hobby, but it will not do much harm if your tank is getting slightly over that. So, if you have big adult fishes who are used to nitrate levels getting around this level, it will not do that much harm.
Other Reasons
With all that being said, nitrates are not the only reason for doing water changes. If you didn't know, your tank water contains many nutrients and minerals that your fish need to thrive. Unfortunately, minerals like Magnesium, Calcium, and many others will eventually deplete, both from the fish and from the tank.
The only way to place this mineral is by doing water changes. Though commercially available products can get that mineral back into your water, these products do not compete with good old-fashioned fresh and clean water change.
If you keep African Cichlid where nitrate levels are usually high, not only those high nitrate levels eventually be bad for your fish, but those levels can also cause changes in your tank's chemistry which can be determinantal to your fish as well. These minerals in your tank water actually buffer your water and keep your pH at a stable level.
Nitrates are acidic, and as they rise in your tank, that acid is fighting against your buffer, which depletes that mineral. So once all these minerals are gone, the buffer that is fighting the nitrate, all of a sudden, your pH level can drop.
In a nutshell, high nitrate can eventually lead to lower pH, and if you keep African Cichlids, you must fight to maintain a high and stable pH. Regardless of what type of fish you keep, if your pH drops too low, you might crash your tank that can cause an Ammonia spike, and that might kill all your fish.
In the beautiful glass box we keep our wet pets in, everything needs to be balanced. So, one thing can easily lead to another, and we have to keep everything stable and in check.
Low-Nitrate Tanks
Heavily planted tanks, tanks with aquaponic systems, or low-stocking level tanks can keep the nitrate level at a shallow level. But even for this tank, water change is necessary every 2-4 weeks, not because of nitrate but because you will still need to replace these essential minerals that your fish and your tank need.
When you settled in your tank, got a dialed-in, figured out a good maintenance schedule, whatever it is, whether you do weekly water changes with monthly filter-cleanings or monthly water changes with only two-filter cleanings a year; whatever that system is, if it is working for you, continue what you are doing keeping your fish happy and healthy.
But if you have fish dying on you occasionally and cannot pinpoint it for an exact reason, then it is most likely your water parameters, which coincides with your maintenance. And if this is the case, you need to do a couple of tweaks to figure out what's going on in your tank. Then, you get things back to cope with aesthetics.
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