When should i do another water change and how much

bettaguy27

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Hello, I have a 20 gallon long with one betta. On another forum they recommended a fish-in cycle, so I started it and it has been about two months. I was changing 50% of the water with prime about bi-weekly until a couple weeks ago when I started struggling with high nitrites. I then started doing daily 50% with nite out 2 and prime. I stopped water changes on tuesday and the tank finished cycling on friday. I was wondering when I should do the next water change, frequency, and how much? Temp is 79.5 F, levels on api test are 6.4(municipal water ph) - 0 ammo - 0 nitrite- 20 nitrate.
 

Oblio

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If you do a 75% change, you will have 5 ppm Nitrate. When levels get at 10 ppm, do a 50% change. This will keep the level at 5-10 ppm. Remember you are removing other things we don't measure for so I would change 50% every 2 (or 3) weeks max even if Nitrates are not at 10 ppm. You can also add terrestrial plants (roots in water, leaves out) such as bamboo or pothos to slow the growth of nitrates.
 

Sgooosh

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If you do a 75% change, you will have 5 ppm Nitrate. When levels get at 10 ppm, do a 50% change. This will keep the level at 5-10 ppm. Remember you are removing other things we don't measure for so I would change 50% every 2 (or 3) weeks max even if Nitrates are not at 10 ppm. You can also add terrestrial plants (roots in water, leaves out) such as bamboo or pothos to slow the growth of nitrates.
floating plants also suck nitrates.
duckweed, water lettuce, and pretty much anything else
 

Colin_T

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Under normal circumstances in a established tank with an established filter, you do a 75% water change and gravel clean the substrate once a week.

If you have an ammonia or nitrite reading above 0ppm, or a nitrate reading above 20ppm, do a 75% water change and gravel clean the substrate every day until the levels are 0ppm.

Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

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What sort of filter is on the tank?
Did the shop tell you how to clean the filter?
 

Byron

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First issue is to clarify the source of the nitrates. I assume the tank water was 20 ppm (post #1), correct? What is the nitrate result for the tap water on its own? This is important because there are different methods needed depending upon the source of the nitrate.

While waiting for that, the point of water changes is stability in water chemistry which improves the fish's health. Removing the various things that cannot otherwise be removed, providing fresh water in place of the "toilet" the fish is in, etc. Nitrates should never be used to gage water changes (meaning, low nitrate so less water changed). If the tank has stabilized, one change per week that is substantial should work, substantial meaning at least 50%, up to 75%.
 
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bettaguy27

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Under normal circumstances in a established tank with an established filter, you do a 75% water change and gravel clean the substrate once a week.

If you have an ammonia or nitrite reading above 0ppm, or a nitrate reading above 20ppm, do a 75% water change and gravel clean the substrate every day until the levels are 0ppm.

Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

--------------------
What sort of filter is on the tank?
Did the shop tell you how to clean the filter?
I’m using a fluval 107 canister with a filter pad and ceramic bio balls in the bottom drawer, and ceramic bio balls in the top drawer. the canister has mechanical filtration as well. the outtake and intake have custom prefilter sponges for betta safety(outtake baffles the current,air stone used to accommodate for the lost surface agitation). a month ago i rinsed the media off in the water change bucket during a wc with the old tank water. I did the nitrate reading again to confirm what it was. What ppm would you say this is?
 

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bettaguy27

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First issue is to clarify the source of the nitrates. I assume the tank water was 20 ppm (post #1), correct? What is the nitrate result for the tap water on its own? This is important because there are different methods needed depending upon the source of the nitrate.

While waiting for that, the point of water changes is stability in water chemistry which improves the fish's health. Removing the various things that cannot otherwise be removed, providing fresh water in place of the "toilet" the fish is in, etc. Nitrates should never be used to gage water changes (meaning, low nitrate so less water changed). If the tank has stabilized, one change per week that is substantial should work, substantial meaning at least 50%, up to 75%.
the tap water is 6.4 ph 0.3 ammonia 0 nitrite 0 nitrate(tank is 0 ammonia shortly after water changes). I redid the nitrate test and am not completely sure what the reading is. I posted the results in the reply above.
 
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Colin_T

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I’m using a fluval 107 canister with a filter pad and ceramic bio balls in the bottom drawer, and ceramic bio balls in the top drawer. the canister has mechanical filtration as well. the outtake and intake have custom prefilter sponges for betta safety(outtake baffles the current,air stone used to accommodate for the lost surface agitation). a month ago i rinsed the media off in the water change bucket during a wc with the old tank water. I did the nitrate reading again to confirm what it was. What ppm would you say this is?
I would say the nitrate is between 10-20ppm. Keep it as close to 0ppm as possible (and under 20ppm at all times) and you will be right. :)

You are cleaning the filter media correctly (in a bucket of tank water), so well done and keep it up :)
 

Byron

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Agree, nitrate is to me nearing 20ppm more than 10ppm. Whichever, the nitrate is solely due to the biological system inside the aquarium, so that makes it easier to deal with. As Colin said, you want it as low as it will go and stay there. With one betta, there is no reason nitrate should be above 5 ppm, in the 0 to 5 range. Nitrates above this are due to overstocking (obviously not an issue here), overfeeding, insufficient water changes, insufficient filter cleanings, insufficient vacuum of the substrate. Live aquatic plants will help a lot, because they are faster to take up ammonia, so there is significantly less nitrite and nitrate. My tanks for 15 years were always in the 0-5ppm range. Some of them had pretty substantial fish loads, but I had lots of plants and always floating, and I changed 60-70% of the tank volume once each week without fail. I also measured pH and it never varied more than 2 or 3 decimal points in each tank all that time. Stability.
 

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