Adding Fuel to the Nitrate Debate: Why Water Changes DONT Reduce Nitrates

[DeLgAdO]

Lets see if we can find a way to test the long term effect of water changes on nitrate levels in an aquarium that has no live plants etc to process nitrates. Hmmmm...........

Does anyone here do weekly water changes? Does anyone test for nitrates every time they do water changes? I for one can answer yes to both of those questions and from experience can say that it is very easy to control nitrate levels with only water changes. I think there are many fish keepers who frequent this site that can also say yes to both those questions.

i do

 

[DeLgAdO]

Nirates will not kill your fish

(dpending on what species of fish it is) they have to be exposed to high concentrations for a long time (years) before you even notice any problems.

tho some are more senstive that others i.e (rays,discus).

nitrates will not kill your fish, however, dissolved organic compounds will.

thats what you should be more worried about.

nitrates are just a component of the total dissolved solids in your water.

 

[Guinness]

My formula is right, Guiness'es is wrong. Sorry

Upon further review, I was incorrect, but not by much. I should not have added the individual days together.

Day 1 = W(WC%)

Day 2 = (W(WC%)+W)WC%

Day 3 = ((W(WC%)+W)WC%)+W)WC%

and so forth.
These are correct.

I tried the discus forum equasions and they were correct for day 1, but that was it. Using their equasions, 10 units nitrate, and 50% wc, I got day1=5, day2=8.75, and day3=107.26
Maybe I'm using them incorrectly, if so please explain.

Dodgefreak, I don't think I'm more inteligent than the next guy, I just want to get this right so that I don't pass on false knowledge in the future.

Guinness

 

[Steve_89]

Waterchanges work for me....and thousands of other hobbyists.

So I will continue with it...regardless of what the article states.

 

[rallysman]

I do a small constant water change (drip) on a heavily stocked tank. My nitrates are slowly dropping over time, and are currently around 30ppm. I'm only dripping 1 gph and the fish seem to be much less skiddish. They seem more comfortable when I come around the tank. They arent freaking out thinking that i'm going to take half of their home away lol.

 

[meiling]

I do a small constant water change (drip) on a heavily stocked tank. My nitrates are slowly dropping over time, and are currently around 30ppm. I'm only dripping 1 gph and the fish seem to be much less skiddish. They seem more comfortable when I come around the tank. They arent freaking out thinking that i'm going to take half of their home away lol.

Isn't that so true, for a short time my parameters were off and the difference in behavior is literally like having a different fish in the tank. G is so mellow and happy and my water is beautiful. We all know generally what seems to be the best for our individual aquariums. In a group situation, we're not all going to agree all the times we discuss or debate.
I've learned a lot watching this thread but it won't change my system of keeping my water great one bit until I get a bigger tank, then we'll see.

 

[shekes]

Maybe I'm using them incorrectly, if so please explain.

If W is the waste produced in one day in the tank it can be expressed as:

W(1) which equals W. The total waste in the tank (after a d amount of days and WCs) can be expressed as a function TWd .

Then after the first WC the waste in the tank is:

d=1, TWd=W(1)-W(WC%),
that is waste produced in one day minus the waste removed by the WC.

Mathematically W(1)-W(WC%) = W(1-WC%)
and not W(WC%) as you wrongly asumed. That is where your mistake is.
W(WC%)is the amount of waste removed by the first WC, a figure we don't need to concern ourselfs with. It is the W(1-WC%) that remains in the tank and poisons the fish.
Note that W(WC%)+W(1-WC%)=W(1)

Then after another day of running the tank before a WC you have

W(1-WC%) (from the first day) + W(1) from the second day:

W(1-WC%)+W(1)

Then, after the second WC it becomes:

d=2, TWd=W(1-WC%)(1-WC%)+W(1-WC%)

d=3,
TWd= W(1-WC%)(1-WC%)(1-WC%)+W(1-WC%)(1-WC%)+W(1-WC%)

Etc. etc.

This is the same as the formula I posted originally, just in a reverse order.

I hope it is clear now.

 

[Guinness]

Mathematically W(1)-W(WC%) = W(1-WC%)
and not W(WC%) as you wrongly asumed. That is where your mistake is.

I didn't adjust that equasion, I made them from scratch. W(WC)= amount of waste in the tank X the percentage removed, thus leaving the amount of waste left in the tank which is what we want to know. If they are wrong, why do they work?

 

[shekes]

That's what I am saying:

W(1) minus the amount of waste in the tank X the percentage removed is the amount of waste left in the tank and is what we want to know, not the amount of waste in the tank X the percentage removed.

I don't know why it works. I don't see how it does. It wouldn't occur to me to calculate actual numbers.

Go through my post again! I guarantee it is correct.

 

[stotty]

Waterchanges work for me....and thousands of other hobbyists.

So I will continue with it...regardless of what the article states.

Regular water changes are the cheapest, safest and most effective way of keeping nitrate concentrations at low level. Only during the tank cycling should ammonia or nitrite be high. Is it not uneaten food, fish waste, decaying plant material that causes Nitrate to go through the roof? So like a large scotch adds water to it it dilutes it? I am no Mathematician but I do 2 x 20% water changes on my tank weekly. I Have to large filters on it and I put my hands up I only test the water every2 -3 weeks but its spot on.