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High Nitrates

1206 Views 2 Replies 2 Participants Last post by  Maryland Guppy
High nitrates seem to be a problem for many.
Whether it be dosing/large bio-load/ or both in combination.

An interesting article from Virginia Tech.
Understanding Fish Nutrition, Feeds, and Feeding | Publications and Educational Resources | Virginia Tech

I found this while investigating a search on "Captive Fish Waste"
This caught my interest.

"Managing Fish Wastes
The most important rule in fish nutrition is to avoid overfeeding. Overfeeding is a waste of expensive feed. It also results in water pollution, low dissolved oxygen levels, increased biological oxygen demand, and increased bacterial loads. Usually, fish should be fed only the amount of feed that they can consume quickly (less than 25 minutes). Many growers use floating (extruded) feeds in order to observe feeding activity and to help judge if more or less feed should be fed.
Even with careful management, some feed ends up as waste. For example, out of 100 units of feed fed to fish, typically about 10 units of feed are uneaten (wasted) and 10 units of solid and 30 units of liquid waste (50% total wastes) are produced by fish. Of the remaining feed, about 25% is used for growth and another 25% is used for metabolism (heat energy for life processes). These numbers may vary greatly with species, sizes, activity, water temperature, and other environmental conditions."

For our aquariums I would rate "consume quickly" @ 1 minute or less, we are not raising commercial fish.

The other bold item is fish waste related. The 50% we deal with in the glass box.
30% is liquid waste that turns to ammonia very quickly and contributes the highest to NH3 in our aquariums.
10% is wasted feed, it decays over time to reach the ammonia state, rather quickly.
10% solid fish waste, poo, crap, mulm, whatever you wish to call it. Most likely the slowest to transform into NH3.
These little ringlets of fish poo seem to be able sustain themselves in a corner of a tank for months before breaking down.

I am writing this because I am targeting the slowly dissolving poo, crap, mulm that is left behind.
Guess I am trying to re-enforce tank maintenance/vacuuming what we can reach easily.

Any thoughts or comments?
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I would only add that fishes don't need to be fed three times a day (like many food container's suggest), unless you are raising fry.
I feed fishes once a day or every other day, and they are fine with this and have been fine over their often suggested lifespan's in literature,expierience.
Less organic input is needed for the fishes/shrimps to thrive than is often thought by many.
Another benefit to less food's being offered is that fishes that might not normally forage along the bottom will do so once they are de-programmed that food's will not be coming thee or four times a day.
This also result's in less organic matter goin into the fishes and comin out = less nitrogenous waste.
Have seen little evidence that inorganic mineral salt KNO3 alone is harmful at even EI level's.
It is the process of organic matter being broken down first into ammonia, and then nitrites, that does the most harm with respect to nitrate's and most level's suggested as harmful from literature I have read ,are not readily seen in most well maintained aquarium's.
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Another benefit to less food's being offered is that fishes that might not normally forage along the bottom will do so once they are de-programmed that food's will not be coming thee or four times a day.
Overfeeding is a great problem for many and they may not even realize it.
All of my fish forage the tank, half remain foraging when they see my shadow get near the tank.

The reason I started this thread was sort of a soft approach to high nitrates.
I hope for more reader input for sure.

Myself and many others in the forum have replied to many threads of others complaining of high NO3 levels.
Always trying to help with advise and suggestions to reduce nitrates.

Primary high Nitrate problems stem from? (Not in any special order)
1. Overfeeding
2. Too may fish / large bio-load.
3. An all in one fert product / KNO3 cannot be eliminated or reduced.
4. Not monitoring water parameters @ all.
5. Lack of water changes ( not a controversial subject in this thread please! )
6. Nitrate in one's tap water.
7. Tank maintenance, vacuum, change filter media, etc....

Inspiration for starting this thread was around fish waste and how it effects our aquarium.
Most think of fish waste as little ringlets of poo that float to the bottom and create mulm.
Mulm is a slow degradation process that takes considerable time.
Uneaten food and plant matter also contribute to mulm buildup.
The plant matter and uneaten foods seem to dissolve/disappear quick though.
The fish poo seems to be a much longer process to dissolve and break down.

Regarding the article I posted 25% of fish excrement is solids.
We all notice this and it is for sure a visual.
We tend not to consider the liquid waste that is 75% of fish waste released right into the water.
A visual representation is not really there, we don't get to see it accumulate on the substrate.
I guess I am trying to bring a realization to the forefront.

I noticed this in the early 80's when I had a grouper and a large trigger in a SW tank.
As they swam by you would notice what they expelled that was not solids.
Reminded me of the haze you notice while driving on hot asphalt north through the desert toward Mexicali.
We typically don't see this with most of our freshwater fish being much smaller etc...
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