What's more effective. Frequent smaller water changes or single huge ones?

[duanes]

Are you gravel vacuuming every time you do a water change?

I do not gravel vac every change, but... if there's excess buildup, I get rid of it,
if every other, or every 3rd water change this occurred, it was sucked out.
I pointed influent pipes so detritus would build up in a certain localized areas, so vacuuming it out was a 2 minute job.
In my heavily planted tanks though, I almost never vacuumed.
As far as the nitrate studies claiming nitrate not overtly toxic, most of that research was done by commercial fish grown for the food market, and usually deals with allowing fish to survive in overly crowded conditions short term, until its time to harvest them, and so they look good as filets, or under plastic wrap.
The long term effect of high nitrate in these studies is usually not relevant, to the food trade, but because the aquarist "might" want their fish to look good, and be healthy long term, per needs are different.
How many times do we see oscars and other large older fish turned in to LFSs disfigured by hole in the head?
And its pretty obvious why, to me, because aquarists take less toxic nitrate to mean, harmless.
I believe "if" the long term effects of nitrate were actually studied, the resulting results would be quite different.

 

[esoxlucius]

I do not gravel vac every change, but... if there's excess buildup, I get rid of it,
if every other, or every 3rd water change this occurred, it was sucked out.
I pointed influent pipes so detritus would build up in a certain localized areas, so vacuuming it out was a 2 minute job.
In my heavily planted tanks though, I almost never vacuumed.
As far as the nitrate studies claiming nitrate not overtly toxic, most of that research was done by commercial fish grown for the food market, and usually deals with allowing fish to survive in overly crowded conditions short term, until its time to harvest them, and so they look good as filets, or under plastic wrap.
The long term effect of high nitrate in these studies is usually not relevant, to the food trade, but because the aquarist "might" want their fish to look good, and be healthy long term, per needs are different.
How many times do we see oscars and other large older fish turned in to LFSs disfigured by hole in the head?
And its pretty obvious why, to me, because aquarists take less toxic nitrate to mean, harmless.
I believe "if" the long term effects of nitrate were actually studied, the resulting results would be quite different.

I shudder to think what could happen to our hobby if somebody actually spent a chunk of their life studying the long term effects of nitrate on aquarium fish in a closed loop environment.

If the results were very very different, as you allude to, and in fact hobbyists all over the world were basically torturing fish by keeping them in an environment where even the slightest measure of nitrate was harming them, then the publishing of such a document would have animal rights activists going berserk. Let's face it, they don't need much of an excuse to get on their bandwagons with their banners.

But then you take into consideration that hobbyists all over the world successfully breed and keep fish for many many years. Do ALL these hobbyists religiously keep their nitrates at 0ppm with daily water changes in order to be successful?

 

[RD.]

I’ve never been overly concerned what some study presents with regards to nitrate toxicity, the bottom line is as nitrates rise (which are easy to monitor with a simple nitrate kit) so does a plethora of pollutants, bacteria, etc, that are known by science to harm a fish over time. IMO Nitrates are not The main issue, and certainly not the only harmful substance when water quality starts to slide.

 

[RD.]

Many people keep fish healthy long term, that have nitrates in the 20 ppm or higher range, right out of the tap.

 

[esoxlucius]

I’ve never been overly concerned what some study presents with regards to nitrate toxicity, the bottom line is as nitrates rise (which are easy to monitor with a simple nitrate kit) so does a plethora of pollutants, bacteria, etc, that are known by science to harm a fish over time. IMO Nitrates are not The main issue, and certainly not the only harmful substance when water quality starts to slide.

That's a good point. If a study was done on elevated nitrate levels in an aquarium they couldn't possibly, with any degree of accuracy pin it down on just the nitrate causing problems, when there would be a plethora of other nasties present to muddy the waters as it were.

And as you say, the nitrate could be the least of the worries.

 

[squint]

Regarding semi-toxic substances -- I've read a couple of places that nitrate doesn't actually become toxic to fish unless nitrite is also present -- is this true or false? (I have no idea).

The gills and integument are impermeable to nitrate. Nitrate is swallowed incidentally by freshwater fish (who don't drink) and converted to nitrite in the digestive tract, same as in humans.

But then you take into consideration that hobbyists all over the world successfully breed and keep fish for many many years. Do ALL these hobbyists religiously keep their nitrates at 0ppm with daily water changes in order to be successful?

Stendker discus 100ppm NO3!

Hello, I was arguing with a hobbyist here that his 50ppm NO3 level is very high for discus and he should be below 20 ppm and ideally below 10 ppm. then he mentioned that Stendker advised to change water when nitrates exceed 100 ppm, I went to their website and found it in the FAQ section...

forum.simplydiscus.com

I've been to the Stendker hatchery. Spent a few hours there and spoke at length with both Jorg and Volker. I was also privileged to have Jorg judge at two British Discus Shows as well as give talks at both. And Volkers talk at the 2012 Swedish show was enlightening!

Their grow out systems are huge (thousands of gallons) and are packed with fish, their stocking density is something like 1 adult discus per 4 to 5 litres of water (or 1 adult per US gallon). They literally ladle the food into each tank. They operate a continual water change system and change very little water a day (approx 10% iirc). The tanks are not what you would expect in as much as they are generally covered in algae and not overly clean either. They operate a simple continual sump system using just sponges, these sponges have rarely, if ever, been cleaned. If the sump starts to back up in one place, they may replace or clean a sponge if it is blocked, but that is about it. When I asked Volker about nitrates, his response was "off the scale".

And despite the above they still seem to grow extremely large discus.

That's a good point. If a study was done on elevated nitrate levels in an aquarium they couldn't possibly, with any degree of accuracy pin it down on just the nitrate causing problems, when there would be a plethora of other nasties present to muddy the waters as it were.

Sure they can and they do it by dosing nitrate to otherwise fresh water.

As far as the nitrate studies claiming nitrate not overtly toxic, most of that research was done by commercial fish grown for the food market, and usually deals with allowing fish to survive in overly crowded conditions short term, until its time to harvest them, and so they look good as filets, or under plastic wrap.
The long term effect of high nitrate in these studies is usually not relevant, to the food trade, but because the aquarist "might" want their fish to look good, and be healthy long term, per needs are different.

What do you consider long-term? You've already made up your mind and nothing can change it. If a study found no effects over 100 years you would argue that it needed to be 101 years. It's an impossible standard to meet.

I could argue that anything is toxic using the same reasoning.



If the effects don't manifest after 8 months at 443 mg/L nitrate in less hardy fish, during the fastest growth rate period, it's probably not going to happen.



No differences in other metrics either...

 

[pops]

All this stuff always made it more complicated to me than I thought it needed to be, I read a university study that said at over 23ppm DMG over time takes place to internal organs. so I always strive to keep a mean number of 20ppm. at water change time it could be any ware between 20 and 35 depending on my creep that week. I always did 90% or fin level water changes. never made sense to me to do more and less water as it made no deference to the fish. also keep in mind you have nitrate creep that happens even with water changes because you never change 100%, so from time to time you will need to do 2 back to back water changes to bring you base line back down.

 

[RD.]

squint makes a very valid point.

 

[squint]

All this stuff always made it more complicated to me than I thought it needed to be, I read a university study that said at over 23ppm DMG over time takes place to internal organs. so I always strive to keep a mean number of 20ppm. at water change time it could be any ware between 20 and 35 depending on my creep that week. I always did 90% or fin level water changes. never made sense to me to do more and less water as it made no deference to the fish. also keep in mind you have nitrate creep that happens even with water changes because you never change 100%, so from time to time you will need to do 2 back to back water changes to bring you base line back down.

What is DMG?

Nitrate creep isn't really a thing. If you play with the Hamza's reef calculator you'll find that nitrate levels reach a limit even with the laziest of water change schedules. Nitrate won't eventually go to infinity because you'll always reach a point where you're removing as much nitrate as was added since the last water change, no matter how small the water change.

 

[pops]

damage, I do not be leave what you say about nitrate creep, again as always IMHO, lets say you have a 100g tank, base line is 0. in a week your nitrate has creeped to 100ppm. you remove 25% of water, and replace, you are now at 75ppm, next water change you are at 175ppm, change 90% and you are 10 ppm, creep next water change well be 110ppm. understand what I am saying? while you are removing nitrate you are not removing it all just as much as you can with fish in. so you are slowly concentrating until you replace it all at some point to bring it back down to base level of 0 or as close as you reasonably can. nitrate is finite, once all is dead no longer fueling the process it stops.