Originally Posted by Flear
reading through the thread more now
regadless of peoples complains about if it counts as weater changes and nitrates building at a faster rate than the water is moving ...
-5 gallons a day
-gradual through the hours it takes, so no matter how extreme the difference is between the water in and the tank there is no stress
-there is zero time spent changing the water only changing the buckets
how many people do weekly water changes at 20% of their tank ?, even 50% of their tank
5 gallons a day for 7 days = 35 gallons of water changed in a week
20% = 200 gallon tank
50% = 70 gallon tank
math off the top of my head
More people do 50% weekly water changes then your probably aware of and for good reasons. Multiple water changes(daily or weekly) do not have an affect that is direct to their sum. Simply put you do two 50% water changes, the next effect is 75% of the original water is changed.
35 gallons weekly
17.5% = 200g tank
50% = 70g tank
5g daily for 7 days, the overall effect is
40.5% = 70g
However the effect of controlling wastes is more disproportionate then this lets on, tho the degree varies depending on the variables. Lets say your tap water has 5ppm NO3 and your tank is stock in a way that the bioload produces approx. 20ppm NO3 per week(heavily stocked).
In comparison to 35g weekly:
- Over one week of daily 5g water changes NO3 levels will be 33.5% higher.
- Over two weeks of daily 5g water changes NO3 levels will be 44.9% higher. -200g tank
- Over one week of daily 5g water changes NO3 levels will be 7.4% higher.
- Over two weeks of daily 5g water changes NO3 levels will be 8.9% higher.
You can certainly have nitrate build up faster then water is changed especially with the daily water changes given how this works and dependent on all the variables. No method works the same for every tank. Tank size, water changed, tap NO3, and estimated NO3 production are all variables here. The overall basic understanding is that multiple small water changes are not equivalent to the same volume single change. However understanding the % difference between these two methods will usually be smaller then the % increase in nitrates levels. This I have always been confident about just haven't ever bothered calculating it out. I had to seek help in calculating this and verifying that its (probably)correct and it only involved cookies, headaches, drugs, and murderous urges. On the bright side I have a pretty awesome excel spreadsheet now.
Additional comparisons using 5ppm tap NO3 and approx 20ppm weekly NO3 production(regardless of tank size).
50% weekly water changes: nitrate will stabilize at about week 6 with 45ppm before a water change and 25ppm after a water change
25% weekly water changes: nitrate will stabilize at about week 15 with 84ppm before a water change and 64 ppm after a water change
Nitrate will always level out... eventually... given the math. The smaller the change the longer it will take and the higher the value at which it levels out.
Also those carrying buckets are crazy, the hose was invented for a reason. 1/2" vinyl costs like 25cents a foot. Also the few minutes of dragging a hose around and doing things while it drains/fills counts as changing water, just like changing buckets counts too.
Large water changes will not stress fish given they are fairly regular and your not changing source waters. Only temp and TDS really have the ability to stress/shock fish, and you still have considerable wiggle room there.