How to Complete a Total Water Change

How to Complete a Total Water Change

So you’ve tried every water treatment under the sun, and your pond still looks like Shrek’s jacuzzi? You may need a complete water change.  A complete water change is necessary in extreme algae or poor water quality cases. If the algae takes over completely and water treatments won’t help your fish become visible beneath the green, cleaning out your pond can help get rid of the algae. When pH levels are very off and the water has very high levels of contaminants that could harm fish and plants, a complete water change can provide a fresh clean start.


A complete water change involves removing all of the water from the pond, scrubbing away algae, removing debris and muck, and then refilling it with fresh, clean water.  Replenishing the water lost from evaporation is not a water change.  As the water evaporates, it leaves behind the pollutants and debris.  Water change requires physically removing water from the pond and adding new water.


Prevention is always the best course of action.  You should try to use water treatments before deciding to do a complete water change to fix any issues.  Complete water changes can be stressful for pond life, and a bit of work.  In an ideal world, all water quality issues are quickly detected and treated before any symptoms show.  It is easier to treat algae before it takes over and depletes the pond of oxygen.  You should perform a water quality test monthly, and try to test biweekly during the hottest parts of summer.  


Performing a complete water change and cleaning out your pond can seem daunting at first, but if you gather all of your materials and go through step by step, it is completely doable!  It takes some elbow grease and a few hours of your time, but your pond and pond life will thank you!


What you will need:
  • Pond pump with tubing (needs to be long enough to discharge the water)
  • Pond vacuum (optional, you could also use a wet vacuum with a hose)
  • Pressure Washer (optional)
  • Rubber boots (wading boots are a great option if you have a deep pond)
  • Rubber gloves (recommended)
  • Place to put your fish- Can use a kiddie pool or large tub.  Large koi need at least a foot of water and room to swim around.
  • Place to put aquatic plants
  • Fish Net (to catch fish)
  • Netting to put over temporary fish home
  • Aeration
  • Garden hose
  • Trash can for debris and muck
  • Buckets (or bags) to transition the fish into the new water
  • Brush or sponge for cleaning
  • Beneficial Bacteria
  • Chlorine Remover plus Conditioner


Step 1: Scoop Out Debris and Remove Water Features and Decorations

You don’t want debris to clog your pump, so use a net to remove all of the debris from the surface of the water. A skimmer fish net will help remove finer debris out of the water.  You can put the debris into a large trash can or bucket.  Clean out any skimmer baskets at this time.


Step 2: Get Rid of the Old Water

You can use your existing pond pump to discharge the water.  Most pond pumps are submersed in the water and do not have any tubing attached.  In order to remove the water, you will need to attach tubing to the pump, and then set it either in a large bucket or in a place that will absorb the water.  Place pump in the deepest part of the pond.


The old pond water is full of nutrients that will be very beneficial for your plants, so it can be easily reused.  If you do not have any nearby plants and want to use it for the grass, make sure you move it every so often so it doesn’t create large puddles.  The mosquitos will love the puddles, especially in the summer.


Step 3: Relocate the Fish and Other Pond Life

The fish’s temporary habitat needs to be filled with their original water to reduce stress and avoid shock from any temperature changes.  Have the pump discharge the water into the new fish holder or if it’s small enough, scoop the clearest water from the pond into the new location.  You need enough room for your fish to swim around and not feel too overcrowded and stressed.  Large koi are going to need more room to swim around.


An aerator should be used in the temporary home so the pond life have plenty of oxygen.  The container should be placed in a shaded area (direct sunlight in shallow water could raise the water temperature quickly). You can place netting over the top of the container so the fish can not jump out, and to protect them from birds, cats, and other predators.


It will be easier to catch the fish if you drain a good portion of the water out.  They will be less stressed if you don’t have to spend an hour chasing them around with a net.  Once the water is low enough, use a Fish Net and scoop each fish out and place them in their temporary home.  


Step 4: Start with the Plants and Decorations

A complete water change is the perfect time to give your plants some TLC.  Your aquatic plants can be placed in a container with water while you clean the pond.  Trim away any dying foliage on the aquatic plants the other plants surrounding the pond.  Plant leaves that aren’t scooped up settle to the bottom of the pond and can turn into sludge.  Use the sponge or brush to clean algae off of the sides of the planters and any decorations.  


Step 5: Clean from the Top Down

Fish and plants are very sensitive to chemicals.  Make sure all sponges, brushes, and any other tools that will be used do not have any chemicals on them.  Do not use soap or any other disinfectant.  A pressure washer can get rid of the most stubborn dirt, no chemicals needed.


When cleaning out your pond, you want to start with the top of the pond and work your way down. All of the dirt, algae, and muck will fall to the bottom, and you can scoop or vacuum it up at the end.  Clean everything you can.  Use this time to polish your pond. Work on any water features that haven’t been removed, like a waterfall.  Use the sponge/brush to scrub away any algae you see, getting into the nooks and crannies of the water features. This is a great time to replace any filters as needed.


You can use a pressure washer or just a hose and a sponge/brush to clean the liner and rocks.  The algae on rocks that feels velvety is beneficial to the pond’s ecosystem.  You don’t need to scrub it all away.  After you have finished hosing down the top of your pond add the pump back in to remove the excess water.  Be careful of sludge and debris surrounding the pump as this can cause a clogging problem, and remember the pump should always have water running through it while powered on.  It can be damaged if running dry.


The bottom of the pond, rocks, and gravel are probably going to contain the most buildup.  A pond vacuum is great for removing a lot of sludge and muck.  If you don’t have a pond vacuum, you can use a spray hose or a pressure washer to clean the bottom, scooping out muck as needed.  You want to remove as much buildup as possible before adding the clean water.  You may need to move the rocks around to get all of the dirt on the backside.  As a reminder, use caution while moving stones around on the pond liner.  You do not want to accidentally create any tears or punctures.


Step 6: Rinse the Filters

You should rinse all of the filter pads on your pumps and water features, and clean the outsides while leaving any of the biological media (whether it’s plastic bio-balls or ceramic media) undisturbed. You could purge the beneficial bacteria that has been growing and establishing itself over time.


Step 7: Reorganize Pond

Add all of your water features, pumps, aerators, and decorations before you start to add your fish.  Wait until you’ve treated the water to add your water.


Step 8: Add Clean Water

Once the pond is nice and clean, you can start adding water back in.  You can use your hose or if you collect rainwater, that is a great option.  Tap water can contain chlorine and chloramines, which are harmful to your fish and aquatic plants if you do not treat the water first.


Step 9: Add Chlorine Remover and Beneficial Bacteria

Chlorine removers are absolutely essential for treating water before adding the fish back in.  City water is treated with chemicals that will harm your fish.  Well and even rainwater can contain contaminants.  Use the a chlorine remover as directed before adding the fish.  The smartpond Chlorine Remover plus Conditioner has an added conditioner to help destress the fish and boost their protective slime coat.


You also want to add Beneficial Bacteria to the new water to give it a boost.  Many of the good bacteria may have been removed in the cleaning process.  Wait at least 48 hours before turning on any UV Clarifiers to allow the new beneficial bacteria to colonize.


Step 10: Test Water

Wait 24 hours until the chlorine remover is in full effect to test the water to make sure there are no issues. Water clarity is not always the same as quality.  Clear water can still have high levels of contaminants or pH imbalance that could harm your fish.


Step 11: Acclimate Fish to the New Water Temperature

Fish can go into shock if their new water temperature is too cold.  Often the new water is colder than the original.  You can fill buckets or bags with the original water and let them float on top of the new water for 15 minutes so they can acclimate.  If you use buckets, periodically splash some of the new water into the bucket to help with the process.


Step 12: Add the Fish

Once the fish are used to the new temperature, you can scoop them out and gently put them back into their clean home.


A complete water change is necessary when your pond clarity and water quality have taken a turn for the worst. Try to think about what caused the issue in the first place.  Was it run off?  Fish overcrowding?  Manually cleaning out all of the sludge, muck, algae, and debris can help give your pond a fresh start, but if you do not solve the problem, it can happen again.  It may take a week or so for your pond’s ecosystem to get back to normal after a total pond water change.  The beneficial bacteria needs to grow back and it’s not unusual to see a little algae spurt or cloudy water temporarily.  Performing a complete water change can seem like a lot of work, but with the proper tools and preparation you can make your pond sparkle.


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