The REAL Facts on Water Changes

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Big_Chubbz created the topic: The REAL Facts on Water Changes

I have a 65g tank (4'x2'x1') that is fully cycled. It is currently stocked as follows (all fish are juveniles):

9 GLOTetras
9 GLODanios
5 Clown Loaches
5 GLOTigerBarbs
11 Neon Tetras

They are fed 3x daily 75cc of OmegaOne Micro Pellets. I test the water daily, and based on my observations the tank is accumulating nitrates at a rate of about 1ppm/day. Ammonia and nitrites are steady at zero.

If my goal is to keep nitrates between 10-20ppm, how often should I change the water? When I change the water, how much can I remove without overly stressing the fish? Simple math would indicate a 50% change every 10 days starting on day 20, but is that too extreme for the fish?

I also have a few logistical questions for people who have been around long enough to give me honest answers based on experience and not necessarily the "By the Book" methods I can easily find with a Google search:

Can I add the dechlorinator to the tank as I refill it with temperature matched water (gradually near the fill tube)?
What is the max percentage that should ever be changed?
What is the max frequency of water changes?
Any extra steps I should take when changing the water (i.e. water additives, etc.)?

Finally, does anyone have any tips on nitrate control? I'm considering constructing a HOB filter planted with pothos to try and eat up some of the nitrates. As the fish grow and I'm feeding them more, I'm sure nitrate production will increase, and I'd like to limit water changes to 2-3 times a month while still keeping levels below 20ppm.


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Rocksor replied the topic: The REAL Facts on Water Changes

Measure your nitrates with a liquid test every 3-4 days at least for the first couple of years until the fish reach adulthood. This will help catch any issues before day 20, such as a sudden spike in ammonia. If it hits close 20ppm do a 50% water change. If you find that you hit 20ppm on day 14, then you can do 50% water change or if you don't have that much time do around 25% in half the amount of days. I know folks with community fish who do large 50% water changes all the time with no issues.

When adding dechlorinator, add the full amount for the total volume, either slowly trickle as you add water or add the total amount in the area of refill before you add the tap water.

There is no max percentage of water to be change. In the wild many fish get 100% water change per second. There are many serious fish keepers who slowly trickle new water into their tanks everyday.

There is no max frequency of water changes. They live in their own sewer, cleaner is better in over all health.

Think of nitrates as second hand smoke. The less exposure, the healthier that the fish will be and the longer they will live. You'll be surprised to find that community fish can live past 7 years of age.

Water additives are not generally necessary unless you have reverse osmosis water or if your water is too soft for the fish that you are keeping.
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