Maybe dump question. How many liters of water did I change?

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professorjimjam

Dovii
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May 26, 2021
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I have a tank that can have exactly 120 liters of water excluding the gravel and plants and other decors. Only water 120 liters
So, Option A) if I remove 50% of the water that is 60 liters and replace it with fresh water 60 liters, anyone can understand the math 60 liters dirty water gone and replaced with 60 liters of fresh water. Optoom B) I changed the water differently, I removed 20 liters of tank water first and then refilled the tank with 20 liters of fresh water and then again removed 20 liters from tank again and refilled it with 20 liters of fresh water and then finally one more time removed the 20 liters of tank water and refilled with 20 liters of fresh water. Hence, it would be wrong to say that I replaced 60 liters of tank dirty water with 60 liters of fresh water. Because for sure I have used 60 liters of fresh water but I didn’t remove exact 60 liters of dirty water like the example given in option A. Becuade, every time I poured fresh water 20 liters it got mixed with the tank water and then when I took out 20 liters put again some portion of the freshwater mixed with the dirty water
So, can anyone please help me understand that if I use option B how much of tank’s dirty water has been replaced from the tank with fresh water?
Appreciate your help!
 
professorjimjam said:
I have a tank that can have exactly 120 liters of water excluding the gravel and plants and other decors. Only water 120 liters
So, Option A) if I remove 50% of the water that is 60 liters and replace it with fresh water 60 liters, anyone can understand the math 60 liters dirty water gone and replaced with 60 liters of fresh water. Optoom B) I changed the water differently, I removed 20 liters of tank water first and then refilled the tank with 20 liters of fresh water and then again removed 20 liters from tank again and refilled it with 20 liters of fresh water and then finally one more time removed the 20 liters of tank water and refilled with 20 liters of fresh water. Hence, it would be wrong to say that I replaced 60 liters of tank dirty water with 60 liters of fresh water. Because for sure I have used 60 liters of fresh water but I didn’t remove exact 60 liters of dirty water like the example given in option A. Becuade, every time I poured fresh water 20 liters it got mixed with the tank water and then when I took out 20 liters put again some portion of the freshwater mixed with the dirty water
So, can anyone please help me understand that if I use option B how much of tank’s dirty water has been replaced from the tank with fresh water?
Appreciate your help!
Click to expand...


I'm not really sure what you're getting at since it's basic math. Say you have 100ppm nitrates and water change water has none. It's always more efficient to do bigger water changes.

Replace 50%(60L) you have 50ppm afterwards.

Or

replace16.6%(20L) = 83.4ppm

replace16.6%(20L) = 69.6ppm

replace16.6%(20L) = 58ppm
 
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The issue I had with doing 1 large water change per week, is stability.
After a large change my tank might test 5 ppm nitrate, an alkalinity of 60 to 80ppm, and have a pH reading of 7.5 to 8.5.
I consider nitrate readings a 20 ppm or higher chronically unhealthy.
But by the end of the end of that week in a semi crowded tank, nitrate might test at 20 ppm or more, an alkalinity 30ppm, or lessr, and pH 6.5 to 7.
I experimented, with differing routines, and found if I do a smaller 30% to 40% water change every other day, the nitrate readings remained at < 5 ppm all week, and alkalinity and pH also remained stable.
In doing it that way, i was changing almost, (or over) 100% of the tanks water per week.
At the time I kept a running log to observe trends.
At the time I was keeping more lacustrine cichlids that come from very stable environments.
 
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Thanks very much Duanes. I will try to change the water every other day. As my tank is semi crowded and my fishes appetite are always very good plus they eat a lot and poop a lot. It is constant work for me to keep the water clean.
 
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Reducing feeding helps a lot in reducing poop and nitrate production. If I do a water change, and then dont feed my fish for 1 week, nitrates do not go up that much in my tank (less than 5ppm). If I feed, 3 times a week, I hit 20 ppm by day 3.

If all the fish are adults (roughly 2-3 years old), then reducing feeding should be done.
 
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Rocksor said:
Reducing feeding helps a lot in reducing poop and nitrate production. If I do a water change, and then dont feed my fish for 1 week, nitrates do not go up that much in my tank (less than 5ppm). If I feed, 3 times a week, I hit 20 ppm by day 3.

If all the fish are adults (roughly 2-3 years old), then reducing feeding should be done.
Click to expand...
I agree, there really is no need to feed adult fish every day, I usually feed two days on, a day or two off.
In reality 3 or 4 days off would be fine after heavy protein type meals, although vegetarians would be the exception to the rule, these fish need to constantly graze
 
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