I wish I had this information when I first started in the hobby. It probably would have extended the lives of many of the fish I previously owned. It is such a simple thing to do, yet many aquarium hobbyists don’t know the importance of performing regular water changes
An aquarium water change should be performed every one to two weeks. The frequency in water changes will be dependent on the bio-load of your tank. The more fish you have, the more water changes you will need to be performed.
That being said, it is not just good enough to know your aquarium water should be changed. You should know why and how much water needs to be replaced each time. By the time you are done reading this article, you should have a good understanding as to how often and why (the benefits) the water needs to be replaced as well how much of the water to be replaced. Let’s get started.
How Often to Change Aquarium Water?
Here is the most important piece of information in this article. If you follow my suggestion, you will have greater success with your tanks. Here goes…
- If you feel your tank is maxed out with fish I would recommend performing a water change once every 7 to 10 days.
- If your tank is not heavily stocked then once every 14 days (two weeks) is perfectly fine. Even stretching it a bit longer will not be a problem.
The reason for the difference is, if you have less fish then there is less feeding and less waste. That means less issues with water parameters.
How Much Water for a Water Change and Why?
If you ask multiple hobbyists how much water they change out, the answers will most likely range somewhere between 10% and 25%.
Personally I shoot for at least 10% if I am changing water once a week. If I am changing water every two weeks, I will probably take out more water, maybe 25%.
Depending on how much waste and excess foods you vacuum up from the substrate, you may need to take out more or less water. If I find I have quite a bit of detritus in the bottom of my tank, I will make a conscious effort not to feed my fish as much and see if that helps.
In general, I think we all overfeed our fish. We try to treat them with food yet it could end up being dangerous.
The more water you take out of your tank for a water change, the more nitrate and phosphates you get out of the aquarium.
What Will Excessive Nitrates and Phosphates Do To Your Fish?
It should be obvious now that you need to get nitrates and phosphates out of your tank. But why?
- An excess of nitrates and phosphates will put your fish’s health at risk. Weaker fish means they will be more susceptible to disease.
- If too much algae is a problem, it could very well be that your nitrates and phosphates are too high.
Topping-Up a Tank Is Not the Same as a Water Change
It’s worth being said that topping up an aquarium with fresh water without taking any out is not the same thing as a water change.
All of the toxins that are in your tank are still there. Nitrate levels are still too high if they were previously.
You can still top up the water, just know that this does not replace a water change.
What does Changing Aquarium Water Mean?
Changing aquarium water is the process of exchanging water from your tank with water that has been conditioned for your aquarium.
You are taking some water out and replacing it.
What Kind of Water Should I Use for a Water Change?
The short answer is it depends what you are trying to accomplish. For a better explanation, please keep reading.
- The water you use can be tap water which will definitely need to be conditioned. Tap water must be dechlorinated. Using water straight from your tap could be dangerous to your fish. Some hobbyists will say they never have a problem doing this and that might be true. I would expect that this would be very rare though.
- Also, if fish could speak, they might let their owner know that the tap water they are using might not kill them but it’s providing them with a miserable life.
- To condition tap water, you can use a number of products. Conditioning is as simple as mixing a preset amount of solution to your water and mixing. If I can recommend one to you I would say go ahead and try this one on Amazon. Aquarium water conditioner.
Another good source of water to use for water changes is RO water. RO water is water purified by reverse osmosis. Quite a few homes will have an RO system installed or use 5 gallon water bottles for drinking water. RO water is about as clean as you can get. There is a pro and con to using this water type. Dependent on what type of a tank you have, whether freshwater or saltwater.
- Using RO water for a freshwater aquarium is fine however, you should know that you are not adding any of the natural occurring minerals that was originally in the water before processing it. Your fish and live plants can benefit from these minerals.
- Using RO for a saltwater tank is a preferred water source as you don’t want to be adding anything extra to the tank. If you do you will be adding it in a supplemental form. Or, it can come from places like the live sand you can use.
For the sake of this article, I am thinking of freshwater tank requirements.
My preferred water source is a mix of RO and tap. I find the more tap water I use the more algae might start growing. I don’t mix the water at each water change. For a couple months, I might just use RO water and then two or three weeks I will use tap water and then flip back. It all depends on how the tank is looking in regards to algae, plant growth and fish activity.
What About Water Temperatures When Changing Water?
You might want to consider what the temperature of the new water is that you are putting in the tank. If you take water right out of the tap, which is cold and condition it, I wouldn’t recommend just putting that in your tank right away. You will most likely shock some of your fish.
I usually use water that is sitting in a container and is room temperature. This still won’t be quite as warm as heated tropical water but much better than straight out of the tap.
I have never had an issue doing this although I do plan to start heating the water in my water change pails very soon.
Conclusion
Now you should know how often to change your aquarium water and the approximate amount you should change each time. To recap:
- Change your water every one to two weeks based on the bio-load (how many fish) in your tank.
- Change out 10% to 25% of the water each water change.
- 10% if you are doing this every week.
- Up to 25% if you are doing a water change every couple of weeks.
Good luck, now let’s go take care of those fish!
Related Aquariums-at-Home Articles.
Why is My Aquarium Water Yellow?
Aquarium Set Up for Beginners.
How to Keep Your Fish Tank Clean Without Changing the Water?
