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How To Change Your Aquarium’s Water

July 12, 2014 by Robert Brand 4 Comments

changing aquarium water
The Python No Spill Water Changer

If you’re new to aquariums, you may be wondering how to change the water in your aquarium. Thankfully unlike so much else when it comes to fish, there is a simple, straight forward answer to this question. Of course that’s assuming that we’re talking about a tank containing one of the more common freshwater species, since certain rare species and brackish water species add a bit of complexity to water changes.

Assuming for now that we’re talking about something like guppies or mollies, changing your aquarium’s water is quite easy to do properly. If you follow the directions below, you’ll be changing your aquariums water like the old, grizzled guy at your local fish store in no time flat.

What You’re Going to Need

  • Gravel Vacuum
  • Clean Buckets (That have never been used for cleaning)
  • Water Conditioner

Before getting started, it’s recommended (though not required), that you scrap all the algae off of the aquarium glass prior to changing the water. This will help to control the algae in the tank, since much of the algae will end up in the water column, and can then be siphoned out of the tank during the water change.

Now before I go any further, I’m going to give a personal recommendation. I cleaned my aquariums for years using buckets before I discovered the Python Water Cleaner. If you want to greatly simplify the task of changing your water, then I can’t recommend this highly enough, and it’s pretty cheap at Amazon.com.

Buy the Python Water Changer at Amazon,com now

So moving on – now that you’ve got everything together, how do you change the water? I know that many people new to aquariums are tempted to do nearly a complete water change every week, but that is one of the worst things that you can do to your fish.

Many of the fish available in the aquarium trade can survive in pretty terrible conditions, so missing a few weeks of water changes usually won’t kill them. What will kill them, is changing the parameters of their water too quickly. When you change too much of the aquarium’s water, you can radically alter the pH or a host of the other parameters – all of which can make your fish ill.

So how much water should you change then? There is no hard rule for this, but a good rule of thumb is to change about 15-20% each week, and more if you’re doing bi-weekly water changes. Never go beyond 30% unless you absolutely have to due to infection or other reasons.

Now that you know how much water to change, the question becomes “how to change it”. If you’re using a Python water changer, is as simple as unplugging all of the equipment from the aquarium (lights, heater, filter), and then attaching the Python water changer to the tap. Flip the nozzle to drain, and drain out 15-20% of the aquarium’s water.

After you’ve drained out approximately 15-20% of the water, switch the nozzle to the fill position, and begin to refill your aquarium. It is important that the tap water be the same temperature as the aquarium water, and a handy trick is to hold the aquarium thermometer under the tap water until it matches the tank water temperature.

After the aquarium has been refilled with new tap water, simply add the Aquarium Water Conditioner and plug all the aquarium accessories back in. Make sure that everything is working again, and you’ve changed the aquarium’s water successfully. You may also need to prime your  filter again, depending on what kind of filter you are using. Don’t leave the filter off for any length of time, because it can cause a bacteria die out, and a mini-cycle in your tank.

If you’re not using the python method, then changing your aquarium water with buckets is still quite similar. First unplug all the accessories from the tank (filter, heater, lights). Then, using the gravel vacuum, drain the water out of the aquarium until you’ve suctioned at least 15-20% of the water out of the tank. After that you can dump the buckets down the drain, though many people use the nutrient rich water to water their house plants or gardens outside.

After the old water has been disposed of, measure the temperature of the water from the taps to get it as close as possible to the aquariums water, and then start to fill the buckets to add to the aquarium. Once the aquarium has been refilled, add the water conditioner and plug all the accessories back in. Make sure that the filter is primed again, and then you’re done.

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Comments

  1. Ray says

    July 30, 2014 at 6:41 pm

    I always fill gallon jugs with conditioner in it. I have always worried about putting tap water directly into the tank before conditioning it.I do have a planted tank so concerned about damage to them. The water around here is very hard and has lots of chemicals.Yes I do like to use the old water for my house plants. What are your thoughts?

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    • Robert Brand says

      July 30, 2014 at 8:40 pm

      I wouldn’t worry about it. The main concern with putting tap water directly into the tank is the chlorine in the water. The chlorine kills off the beneficial bacteria in the tank (which is mainly contained in the filters), so as long as the filter is turned off – or removed in the case of a sponge filter, a brief exposure to untreated water won’t hurt the tank. I have extremely hard water where I live too, and its municipal water so lots of fun stuff is added to it. But I’ve treated the water after adding it for years, and all of my plants are doing great.

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  2. pidgeroo says

    August 8, 2016 at 6:32 am

    How often should I clean the pump and how do I know when to replace the charcoal? Also, even though I clean the spongy parts and the charcoal bag, it will always puff out a load of dirt when I switch it back om leaving me feeling that I needn’t have bothered putting in clean water!

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    • Robert Brand says

      August 8, 2016 at 10:43 pm

      I like to clean mine weekly, and while you should clean the sponges, you don’t need to worry about cleaning it too much. There is a lot of beneficial bacteria on the filter inserts, and if you clean it too much, you might damage you aquarium’s ability to process waste products.

      I do like to really clean the filter itself, and sometimes I’ll take it to the sink to give it a good scrub. But you should never expose your filter to tapwater, as the chlorine will kill all of the bacteria on it quickly. After I clean the filter, I give it a good rinse out with tank water.

      It won’t be perfect, and to be honest with you, I still get a bit of the ‘gunk’ blast when I turn on it. But it’s not nearly as bad as it looks, and you’ve actually cleaned out a significant amount of fish waste and detritus from the tank.

      Edit: Forgot to mention the charcoal inserts. I think the charcoal inserts last up to six weeks, and then start to leech contaminants back into the water. I used to cut them open (Depending on the filter) and empty out the charcoal, and leave the rest of the insert in for beneficial bacteria to grow on. You don’t need charcoal unless you have contaminants in your water, or you’re trying to actively remove something from the water like medication after treating your fish. Otherwise, while it’s nice, it’s not necessary. Plus, then you save a lot of money by not having to buy them every month or so.

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