Water Changes...Unnecessary?

[skjl47]

hello; Please continue with the nitrate debate. However for me and maybe many others the point is how to keep better water. That we can measure nitrate and it is considered an endpoint in the nitrogen cycle keeps it front and center in many posts.
Long before I knew of home nitrate measure test kits I had started to do WC's. Mainly to dilute dissolved mineral salts and any other things that may be dissolved in my tank water. I started keeping tanks back when all we did was to top off a tank with more water. Not sure how I came around to doing regular WC but when I did get there I found WC to be a better practice.
To the OP, whatever may be in the source water without regular WC much of that stuff will increase in concentration with evaporation. Add to this the organic byproducts from the metabolism of the lifeforms in a closed system. To attempt to be more clear, even if the source water is high in something like nitrates, after a while without WC and with only top offs the stuff will be more concentrated.

Two more things to consider. One is that a WC is a chance to also siphon out detritus. This seems a good practice.

Another is a question of the test results. Have you used a standard to calibrate the nitrate test? By this I mean using something like distilled water. Test a vial of distilled water which should give a null for nitrates.
Also use distilled water to clean all the test vials in between tests.
Am I correct in that the nitrate test requires very vigorous shaking?

 

[Coryloach]

eep reading, and eventually you will find that

Exaclty, I keep reading and I find nitrate is not an issue....It's just a small component of an entirely bigger picture. By doing water changes one may think they're controlling nitrates, but they're doing a lot more than that. The only issue I find is that nitrate tests are no good at determining pollution levels....So not a good measure to tell you when to water change if one is not up to regular large water changes.

 

[squint]

You are getting my message wrong. I didn't post that to argue about nitrate levels being toxic. That study is only brushing/stating exact numbers. What I posted it for is for it actually reporting that nitrate levels in high flow systems are not an issue. It is in the low flow systems that it becomes an issue, i.e. systems in which the flow rate through the filter is reduced....e.g. denitrification going on....

Right...and I'm trying to track the sources down so I can read their exact words. But I'm not finding anything about nitrate limits whether for low flow or not in the original source...

 

[Coryloach]

Right...and I'm trying to track the sources down so I can read their exact words. But I'm not finding anything about nitrate limits whether for low flow or not in the original source...

No you won't. And that's the funny part of most studies, they give numbers on nitrate toxicity and nothing else to back it up, just some other fool's conclusions... Yet, they get quoted on fish forums as absolute truth. Some of the other studies I posted are comprehensive. I personally don't take any notice of studies that don't give measures of all important water chemistry changes throughout their studies such as ammonia, nitrites, oxygen, etc...If you keep in mind that nitrate and nitrite are very closely related, you'll start finding their relation in all studies of toxicity of nitrate....

 

[Coryloach]

nother is a question of the test results. Have you used a standard to calibrate the nitrate test? By this I mean using something like distilled water. Test a vial of distilled water which should give a null for nitrates.
Also use distilled water to clean all the test vials in between tests.
Am I correct in that the nitrate test requires very vigorous shaking?

Have you researched using conductivity/TDS meter as an alternative? You don't need to shake anything anymore and although it gives a total measure of dissolved ions, not just nitrate, it is actually a better way of tracking water quality as anything you add to a tank will increase TDS/conductivity, inclusive of fish waste, dissolved organics, etc.. A cheap, rather accurate one can cost as little as 20 quid and last years if you take care of them. It may need calibration from time to time....It takes 2 seconds to measure..

 

[skjl47]

Have you researched using conductivity/TDS meter as an alternative? You don't need to shake anything anymore and although it gives a total measure of dissolved ions, not just nitrate, it is actually a better way of tracking water quality as anything you add to a tank will increase TDS/conductivity, inclusive of fish waste, dissolved organics, etc.. A cheap, rather accurate one can cost as little as 20 quid and last years if you take care of them. It may need calibration from time to time....It takes 2 seconds to measure..

Hello; Thanks for the info. I have not checked out these meters.

 

[Coryloach]

Hello; Thanks for the info. I have not checked out these meters.

As a quick reference, once you get a hold of one of those, you need to compare tap conductivity(or the water you use to do water changes with) to tank conductivity. If the tank's conductivity/TDS is significantly higher, the tank has become polluted....A conductivity/TDS meter will measure anything that has dissolved in water, measuring anything that has the ability of affecting fish health. One doesn't even need to know the break down of individual dissolved ions...

 

[squint]

No you won't. And that's the funny part of most studies, they give numbers on nitrate toxicity and nothing else to back it up, just some other fool's conclusions... Yet, they get quoted on fish forums as absolute truth. Some of the other studies I posted are comprehensive. I personally don't take any notice of studies that don't give measures of all important water chemistry changes throughout their studies such as ammonia, nitrites, oxygen, etc...If you keep in mind that nitrate and nitrite are very closely related, you'll start finding their relation in all studies of toxicity of nitrate....

I was actually trying to track down the source for your argument that nitrate should be kept below 10 mg/L NO3-N in low flow or recirculating systems.

What's the relationship between nitrite and nitrate? I don't think it's that easy for nitrate to be converted to nitrite. My ammonia and nitrite levels are pretty low (0.02 NH3-N and 0.012 NO2-N) so I can't say I've noticed a relationship with nitrate.

 

[Coryloach]

I was actually trying to track down the source for your argument that nitrate should be kept below 10 mg/L NO3-N in low flow or recirculating systems.

Totally not my argument On the contrary I don't think nitrates are an issue at all. I posted the study as it points out that nitrate toxicity levels differ in high flow vs low flow systems...hence it is not the nitrate the issue in the first place...It is oxygen levels in the filter.

What's the relationship between nitrite and nitrate? I don't think it's that easy for nitrate to be converted to nitrite.

The relationship is denitrification which naturally occurs in either dirty filters used as siphons for aesthetics or deep anoxic/anerobic substrates, or tanks with low oxygen in general for a range of other reasons. I posted my thoughts on nitrate toxicity and its relation to nitrites in post #18

 

[Hendre]

Just do your water changes folks. Won't hurt.

I keep an eye on my nitrates, when they hit 40ppm in a shrimp tank I lost most of them to a bacterial infection. I also check on my planted tank to make sure that the plants have food.

I believe that somewhere RD. made a post about higher nitrate levels and farmed fish, giving bacteria more substrate on a fishes gills. Thus leading to potential infection.

Anyway, at the end of the day nitrate is just one of the few things to look out for and we should try to keep it low regardless.

And N nishikigoi21 try water sprite, it's a very fast growing surface plant and should help with your nitrate!