What gph are you pushing ?
Anoxic filter build
- Thread starter Rhyno8
- Start date
What gph are you pushing ?
Believe it’s 525gph but need to check.
I have a sump now and will be trying in there soon.
Anoxic filter, i.e. filter in which denitrification is promoted is a knife with two blades, especially in a heavy bioload tank...
A lot of the studies on toxicity of high nitrates(NO3) report elevated nitrites(NO2) specifically due to denitrification occuring..
Nitrate Toxicity: A Potential Problem of... (PDF Download Available). Available from: https://www.researchgate.net/public..._A_Potential_Problem_of_Recirculating_Systems [accessed Apr 11 2018].
"Fish exposed to the sodium nitrate and potassium nitrate began to die after six weeks at the elevated nitrate levels (200ppm)
With the exception of nitrate concentrations purposefully outside these ranges, our water quality was within the proposed
ranges for all water quality parameters except for nitrite. When nitrate levels were elevated due to
addition of a nitrate salt or from nitrification, increased nitrite levels were observed. This increase
in nitrite was most likely due to enhanced reduction of nitrate to nitrite caused by the elevated nitrate concentrations"
And another one below that tested nitrate toxicity by setting up two groups, one with low nitrate and one with high nitrate. See what happens in high nitrate environment...
Comparing the effects of high vs. low nitrate on the health, performance, and welfare of juvenile rainbow trout Oncorhynchus mykiss within water recirculating aquaculture systems
https://www.sciencedirect.com/science/article/pii/S0144860914000041#tbl0020
Several other water quality parameters were significantly different between treatments. These parameters included nitrite nitrogen......Nitrite nitrogen, total suspended solids, boron, and potassium concentrations were significantly greater within the high NO3-N treatment.
So generally speaking one is playing with fire when promoting denitrification because denitrification can occur only partially, thus leaving you with nitrite spikes.
I have emersed planted baskets which clay pebbles and I put the flow of the filters over them on purpose, to prevent them from becoming anaerobic/anoxic. I also drain them each week with the water change. I've never had a nitrate issue this way and I've been using them over the last 5 years, plus the baskets are planted with enormous beautiful plants that tend to flower every so often. Why would one want an anoxic filter in an environment dependent on oxygen is beyond me. Plus deep anoxic, static substrate will promote the development of unwanted pathogens....
Plants take up nitrogen directly, in all forms and they've preference for ammonia, so the entire nitrification and denitrification is by-passed, thus not risking either nitrite spikes, neither low oxygen levels...
Here are my nitrogen eaters...
The baskets...as simple as filling with clay pebbles, sticking a plant in and giving the plants light, the pebbles flow over/through. They've got holes drilled at the bottom and on the sides.
I use round clay pebbles and not gravel or cat liter to avoid anoxic/anaerobic conditions in the roots...
Call it aerobic plant enhanced filtration by Coryloach, lol.
Don't believe it doesn't work well enough to reduce nitrogen? See chronic nitrogen deficiency on same plants.
Even if one has some denitrification occurring releasing NO2 instead of N2, the plants will gladly mop it. Where non-planted baskets will just let that out in the water column poisoning the fish slowly.
Here are my nitrogen eaters...
The baskets...as simple as filling with clay pebbles, sticking a plant in and giving the plants light, the pebbles flow over/through. They've got holes drilled at the bottom and on the sides.
I use round clay pebbles and not gravel or cat liter to avoid anoxic/anaerobic conditions in the roots...
Call it aerobic plant enhanced filtration by Coryloach, lol.
Don't believe it doesn't work well enough to reduce nitrogen? See chronic nitrogen deficiency on same plants.
Even if one has some denitrification occurring releasing NO2 instead of N2, the plants will gladly mop it. Where non-planted baskets will just let that out in the water column poisoning the fish slowly.
Last edited:
Thats some crazy plant growth! The design of this filter isnt 100% devoid of oxygen its anoxic not anaerobic it works on different principles http://www.mankysanke.co.uk/html/anoxic_filtration.htmlPlants take up nitrogen directly, in all forms and they've preference for ammonia, so the entire nitrification and denitrification is by-passed, thus not risking either nitrite spikes, neither low oxygen levels...
Here are my nitrogen eaters...
The baskets...as simple as filling with clay pebbles, sticking a plant in and giving the plants light, the pebbles flow over/through. They've got holes drilled at the bottom and on the sides.
I use round clay pebbles and not gravel or cat liter to avoid anoxic/anaerobic conditions in the roots...
Call it aerobic plant enhanced filtration by Coryloach, lol.
Don't believe it doesn't work well enough to reduce nitrogen? See chronic nitrogen deficiency on same plants
I feed the fish as much as I want
"The term anoxia means a total depletion in the level of oxygen, an extreme form of hypoxia or "low oxygen".
"Anaerobic - relating to or requiring an absence of free oxygen."
Anaerobic = total absence of free oxygen (O2) or bound oxygen (NO2, NO3)
Anoxic = absence of free oxygen, but presence of bound oxygen.
In a rooted basket, no matter the substrate, the area around the roots will be oxygenated because roots release oxygen. That means that nitrification will occur alongside direct plant uptake of ammonia. You've got two good worlds in one. In time the entire basket is riddled with plant roots...A massive capacity for filtration that both reduces nitrogen and also detoxifies ammonia and nitrite if needed, plus of course plants also consume nitrogen in all 3 forms....and a ton of other compounds such as phosphate, calcium, magnesium, iron, copper, etc...etc...
The line between anoxic and anaerobic is very thin, If you set it up badly, it will always end up anaerobic, in time it definitely will if the detritus is not flushed out...Then it will be like having the bioload of a monster in your tank...
The line between anoxic and anaerobic is very thin, If you set it up badly, it will always end up anaerobic, in time it definitely will if the detritus is not flushed out...Then it will be like having the bioload of a monster in your tank...
I feed the fish as much as I want
"The term anoxia means a total depletion in the level of oxygen, an extreme form of hypoxia or "low oxygen".
"Anaerobic - relating to or requiring an absence of free oxygen."
Anaerobic = total absence of free oxygen (O2) or bound oxygen (NO2, NO3)
Anoxic = absence of free oxygen, but presence of bound oxygen.
I still have alot to learn haha ill keep experimenting but on the small tank i think see how things pan out. Its always interesting trying new things. Gotta buy a heater today and finish setting up.
That's why I posted the studies for you to read....That "different" principle is nothing new....That's how deep substrates work in general, they become anoxic and even anaerobic, e.g. deep sand layer in a fish tank.....There's numerous issues that may occur and the most notable is nitrate to nitrite reduction in a tank(heavily stocked tank) but also hydrogen sulfate, methane, pathogenic bacteria, and actually ammonia production rather than ammonia consumption, etc.......Why do you think monster fish keepers resort to thin substrate or no substrate at all? It's because subconsciously they've figured something isn't right in a non-planted deep substrate tank.... Otherwise, we can all fill the tank several inches with cat litter and there's your biocenosis basket....I'd stick to promoting high oxygenation but experimenting is always good. ....Good luck and please keep the progress. I don't mind being proven wrong because that's how we all learn.
Last edited:
