Why a weekly 50% WC is better than two weekly 25% WCs

[ScatMan]

THe 25%x2 a week never reaches the same max nitrate levels as the 50% once a week.... omg... open your brain.

seriously though, you're making the exact same incorrect assumption that jlnguyen74 already made. it might do you some good to re-read the thread to take a fresh look at it all.

i'm not trying to bust balls here or say "i told you so", i just want everyone to understand.

please forgive my rudeness, my frustration got the better of me. i'm sorry.

 

[ScatMan]

So what about those running constant drip systems? What would the data look like for someone who dripped 10% a day, versus someone who did a 70% weekly water change? Same pattern?

i would assume it to have similar results to op's example (higher average ppm with the drip vs wc) because a drip is basically a whole bunch of tiny water changes. calculating that would be virtually impossible though.

this would probably be a fun experiment for you to try! jk

 

[calioutlaw1a]

THe 25%x2 a week never reaches the same max nitrate levels as the 50% once a week.... omg... open your brain.

After pages of arguing and you now say this? This is simply false, and this is where the hang-up is. I do appreciate your discussion here though because it perfectly exemplifies why I made this post, and why in my original post I said that it isn't necessarily intuitive to see why a larger water change is better than multiple water changes with an equal total volume in a given time period.

The total volume of water changed is equal in both cases, the time period is equal in both cases, and the maximum nitrate is equal in both cases. The only difference is the minimum nitrate level in each case, which is lower with a single larger water change resulting in an overall lower average nitrate level.

Your statement should read:
"The 25%x2 a week never reaches the same min nitrate levels as the 50% once a week.... omg... open your brain."

 

[jlnguyen74]

Look at the charts; both scenarios never hit 40ppms; they peak at 32-35ppms.

the 50% 1xpw will reach 40ppm about a week faster than 25% 2xpw.

it's much more important to note that the fish in the 25% 2xpw tank will spend the rest of their lives at a 5ppm higher average nitrate level than the fish in the 50% 1xpw tank.

were you trying to make a point or just asking the question? because vfc took the time to make and post charts that answered this question, it would be nice if you took the same time and courtesy to look them over.

How were those charts data obtained? Actual test after every water change, or just some formula, best-fit curve?

 

[jlnguyen74]

I live by the old Army Corps of Engineers dictum of;
"The Solution to Pollution is Dilution"

Math aside, the more often one flushes their fishes toilet, the better.

Yet some guys think they're smarter than Army Corps of Engineer!

 

[ScatMan]

How were those charts data obtained? Actual test after every water change, or just some formula, best-fit curve?

just some formula, what's your point?

 

[ScatMan]

Yet some guys think they're smarter than Army Corps of Engineer!

50% wc 1x per week will dilute more than 25% 2x per week...

being smarter or dumber than the army corp of engineers does not change this fact.

 

[vfc]

How were those charts data obtained? Actual test after every water change, or just some formula, best-fit curve?

Excel formulas using your input parameters from your original post:
Bio-Load 20ppms/week (~3ppms/day), tank starts with 20ppms nitrate, 25% twice a week (I used 3 days because my calculation can't handle 1/2 days) vs 50% weekly (6 days).

 

[vfc]

When the larger/longer vs smaller/shorter WC horse stops moving; I'll post my 2 vs 4 filter charts in a new thread that show how more filtration (mechanical) can actually increase nitrates. That has the potential to generate some more lively debate.

Keep in mind this forum is both educational and entertaining. I, for one, like a good argument along with some name calling. Some of the "you're a moron" responses make me laugh. It's all good.

 

[jlnguyen74]

just some formula, what's your point?

Excel formulas using your input parameters from your original post:
Bio-Load 20ppms/week (~3ppms/day), tank starts with 20ppms nitrate, 25% twice a week (I used 3 days because my calculation can't handle 1/2 days) vs 50% weekly (6 days).

All the argument over Excel formulas...

50% wc 1x per week will dilute more than 25% 2x per week...

being smarter or dumber than the army corp of engineers does not change this fact.

The problem is it's not a fact. It's only a theory from Excel formula