Anoxic filtration

Post all Pond construction Topics here including DIY bits and pieces

Moderators: B.Scott, vippymini, Gazza, Manky Sanke

Dave Collins
Nurse Shark
Nurse Shark
Posts: 90
Joined: Sun Aug 05, 2007 10:48 am
Location: Nr Strasbourg, France

Anoxic filtration

Post by Dave Collins »

As far as plans are concerned I am looking for an area to set up anoxic filtration as I have a problem with high nitrates during the summer seasonBest regards DaveB


Hi Dave

Did you ever get started on this project ?

Mine's been running for nearly 4 and half years now and is giving me some fairly good water results. Nitrate is down from over 200 (unreadable really) to around 33 mg/l and I'm still feeding 330 gms of 36% protein food a day. As always I have far too many fish.......... :oops:
Manky Sanke
Site Admin
Site Admin
Posts: 554
Joined: Sun Apr 16, 2006 10:24 am

Re: Anoxic filtration

Post by Manky Sanke »

While we are waiting for Dave B to answer, you seem to have done very well with this system so, out of curiosity, how many baskets and how many koi are we talking about?
Dave Collins
Nurse Shark
Nurse Shark
Posts: 90
Joined: Sun Aug 05, 2007 10:48 am
Location: Nr Strasbourg, France

Re: Anoxic filtration

Post by Dave Collins »

I currently have 60 biocensus baskets that are just about coping, I need a faster flow to get nearer to zero. I used to have 50 koi but have managed to reduce the numbers down to about 40 although they refuse to line up so that I can get an accurate head count. The reduction in numbers hasn’t helped as much as I thought because they keep growing. There are about 20 Koi of 65cms or over and the obligatory Chagoi at about 80cms.

Advantages of Anoxic system. Stable pH, the filter doesn’t “use” any KH. The Nitrate has gone from 150-200mg/l down to 25-30mg/l.

Crystal clear water. Reduced filter cleaning from twice a week to once per year.

Happy Koi keeper :D
Manky Sanke
Site Admin
Site Admin
Posts: 554
Joined: Sun Apr 16, 2006 10:24 am

Re: Anoxic filtration

Post by Manky Sanke »

Thanks for that memory jog Dave,

I'm just finishing a short eBook about the importance of KH in relation to pH stability for the Koi Organisation International book store. My remit is to focus more on the water chemistry of various ways of increasing KH rather than filter systems themselves so I've only briefly mentioned the demand that conventional filtration makes on KH. I hadn't thought to mention that anoxic filtration doesn't use any KH because the baskets become homes to different bugs than the aerobic ones that live in conventional biofilters. I won't cover anoxic filtration in any great detail either but it would be good to mention that it doesn't reduce the KH.

Thanks again.
Dave Collins
Nurse Shark
Nurse Shark
Posts: 90
Joined: Sun Aug 05, 2007 10:48 am
Location: Nr Strasbourg, France

Re: Anoxic filtration

Post by Dave Collins »

Now I've got your attention Syd,

Can the Anoxic filter also remove pheromones from the water ? :?: I have no evidence but I think it might as I'm overcrowded and the Koi are still growing.

Any pearls of wisdom ?
Manky Sanke
Site Admin
Site Admin
Posts: 554
Joined: Sun Apr 16, 2006 10:24 am

Re: Anoxic filtration

Post by Manky Sanke »

For anyone reading this who might need an explanation of what a pheromone is; pheromones are large complex molecules consisting of a long base of carbon and hydrogen atoms with other molecules either joined on or replacing some of the hydrogen or carbon atoms. It's these additional molecules that give each pheromone its individual characteristic.

In the aquatic environment pheromones can be likened to underwater smells of different types. Some of these "smells" are attractants such as the "I'm ready for spawning" pheromone which kicks off the spawning behaviour of several fish at once, some are repellents such as the fear pheromones which say; "I'm scared let's get out of here". The "inhibit growth" hormone is a behaviour modifier. It's continuously released by fish and, in a large lake with a low population of fish, it becomes so diluted that it has no effect on the other fish. In a smaller lake, or as the fish population grows, the cumulative effect of all the growth inhibitors that are excreted is to reduce the growth rate of the fish. This is evolutionary advantageous because it regulates the growth and population size of that fish species so that they don't outgrow their space or food resources.

With a basic make up of carbon and hydrogen atoms these molecules are called organic molecules and provide a source of nutrients and energy for heterotrophic bugs .

So, to answer the question (as far as I can), it's certain that pheromones can be broken down by heterotrophs. It's also certain that a multitude of different heterotrophs live in the centres of the baskets and would make short work of breaking down any pheromone that entered zone C in the diagram below. I'm reasonably sure that pheromones will be drawn into the baskets so I believe the answer to your question is "yes" the biocenosis baskets do reduce pheromones including the growth inhibitor BUT....

The biochemistry that takes place inside the baskets is the stuff of nightmares. I'm pretty sure that long chain carbon and hydrogen molecules will be drawn inside but I can't be certain so I've wimped out! I've asked Kevin whether my assumption is correct and I'll get back to you as soon as I get his answer.

Image
Dave Collins
Nurse Shark
Nurse Shark
Posts: 90
Joined: Sun Aug 05, 2007 10:48 am
Location: Nr Strasbourg, France

Re: Anoxic filtration

Post by Dave Collins »

Thanks Syd, good answer by the way, over to you Kevin.
Airlite
Nurse Shark
Nurse Shark
Posts: 65
Joined: Wed Oct 14, 2015 11:24 pm

Re: Anoxic filtration

Post by Airlite »

...^^^... And that's why this forum should continue ad infinitum. Great information for the uninitiated.

M :-)
Manky Sanke
Site Admin
Site Admin
Posts: 554
Joined: Sun Apr 16, 2006 10:24 am

Re: Anoxic filtration

Post by Manky Sanke »

Thank you, it's a pleasure to add accurate and reliable information to the general pool of knowledge which is why Duncan and I want lots of questions that we can answer.
Dave Collins
Nurse Shark
Nurse Shark
Posts: 90
Joined: Sun Aug 05, 2007 10:48 am
Location: Nr Strasbourg, France

Re: Anoxic filtration

Post by Dave Collins »

Thought I'd explain a bit more about my Anoxic filtration whilst I've got everybodies attention. :wink:

For those who are curious about this type of filter or who are even considering installing one, I thought I’d write about my experiences of running one for the last 4 and half years. What are the advantages and disadvantages of this kind of filter?

Disadvantages
I’ll start with this first because it’s much easier. The Anoxic filter is a bio filter only, so although this is not strictly a disadvantage, it does require some sort of solids removal system as a first stage. Depending on how the Anoxic container is constructed then it can take up a fair bit of surface area unless you stack the baskets vertically.

Advantages
These are many but I will try and explain a few of them.

Cost. As in everything in life nothing is free BUT there is no need to spend thousands chasing the nitrogen cycle. I currently have 60 biocensus baskets in a liner pond that filters the main pond. The baskets were filled with cat litter and Laterite although there are now cheaper alternatives available to Laterite. Baskets, litter and Laterite worked out at £19’s each so not cheap but could be reduced to about £12’s today. The Laterite has a reported life of at least 20 years and the baskets and cat litter are forever.

Water parameters. The Anoxic filter will first “eat” ammonia, so as such there is no nitrogen cycle except for the bacteria living on all pond surfaces. As there is very little ammonia then nitrite is also low and is consumed by the filter when it has finished with the ammonia. Once this is in short supply then the filter will start to consume the nitrate and phosphate leaving the water clean. The filter has no influence on KH or pH so the pond is very stable, I have been running my pond with a KH of 2dh for years with no signs of any change. So the pond water is very good. :D

Cleaning. I have an RDF fitted so there is very little dirt that gets into the Anoxic filter. All I have is a very light covering of mulm on some of the baskets (between 1 & 2 mm thick). I last cleaned the Anoxic filter on 4th October 2013 8) and have no plans to clean it in the near future.

Water changes. I don’t change the water at all and haven’t done so since installing the Anoxic filter. I top up with about 200 liters of RO water a day that is used by the RDF but that is all for my 45,000 liter pond. The pond is crystal clear and all parameters checked on my Hanna 83203 electronic meter are low. Current temperature is 9.4°C and I’m still feeding 250 gms of 36% protein food a day.

Koi. I have about 40 koi in the pond of which 20 are over 60cms. They are all looking very well and I’m hoping my Chagoi which is currently at 85 cms will pass the 1 meter mark in the next two years. The Koi are growing well but I don’t feed for quick growth so there are no growth records being broken in my pond. The Anoxic filter also consumes growth suppressant pheromones which would explain why the Koi in my overcrowded pond are still growing.

Conclusions. I wish I’d found the Anoxic filter system before I spent thousands on all sorts of fancy filter systems that only leave you with a pond full of nitrates and a very large water bill trying to eliminate them.
phill3344
Sandbar shark
Sandbar shark
Posts: 4
Joined: Wed May 20, 2015 4:43 am

Re: Anoxic filtration

Post by phill3344 »

Thoroughly interesting read. Would like to look at this in the future. Is there a basket amount /size per gallon or per fish calculation to look at. Our any guidance to more reading.
Thanks
Phill
Dave Collins
Nurse Shark
Nurse Shark
Posts: 90
Joined: Sun Aug 05, 2007 10:48 am
Location: Nr Strasbourg, France

Re: Anoxic filtration

Post by Dave Collins »

Hi Phil,

You'll have a good read here http://www.mankysanke.co.uk/html/anoxic_filtration.html :mrgreen:
Airlite
Nurse Shark
Nurse Shark
Posts: 65
Joined: Wed Oct 14, 2015 11:24 pm

Re: Anoxic filtration

Post by Airlite »

Hi Dave,

I'm seriously looking at the anoxic filter system for my small 1500gal yard pond. I'm currently managing with a 2 chamber (brushes+jap mat) filter that has worked remarkably well but cleaning it is a laborious and messy procedure. I'm constrained by the fact that there's no room in the back yard to create the anoxic filter pond but I could build a small one in my garage where the current filter is located. Something in the order of 1.8m x 0.6m x 0.6m would allow me to have 20+ baskets if I double stack them I think. I have don't have any form of pre- filter at the moment and I'm asking for advice/recommendations on another forum but I'm drawn towards a rotary drum filter although, as yet, I don't know which one would suit me best (compact size is obviously a consideration).

I take it light is not important for the anoxic filter system to work? I know if I was intending to plant up the filter then being inside the garage would be problematic but I figured if I want to grow stuff in there at some point in the future I can add a skylight or install some fancy LED sun lights to overcome the gloom. At present I'd like to build the filter in such a way that I can cover the top and use the available space as a worktop to put my microscope/test kit/meds and associated material. This would also help me reduce the mozzie/midgy/blackfly population currently enjoying residence in my conventional filter set up.

Any advice to a newcomer about to take the anoxic plunge would be very useful - I've read, reread and read again Manky's articles on the subject - it's more the practical things I need to do or avoid doing that would be really useful. Thanks as always, Mick.
Manky Sanke
Site Admin
Site Admin
Posts: 554
Joined: Sun Apr 16, 2006 10:24 am

Re: Anoxic filtration

Post by Manky Sanke »

Mick,

I appreciate your attempts to learn by heart my witterings about anoxic filtration :wink: but don't forget Kevin Novak's original book on the subject. You can download it for free from iTunes (the link is at the end of my article) and there's a lot of technical information in there, including a case of someone who built a system in his garage.

The baskets work better if they are planted but, apart from that, you can even install them in total darkness under a worktop and the bugs won't care. If you want to have planted baskets in your garage, you could obviously install suitable lighting but have you looked for suitable plants that don't need much light? I can't think of any at the moment but it could be worth a quick search to see if you can find something you like that's tolerant of a low light level.
Dave Collins
Nurse Shark
Nurse Shark
Posts: 90
Joined: Sun Aug 05, 2007 10:48 am
Location: Nr Strasbourg, France

Re: Anoxic filtration

Post by Dave Collins »

Hi Mick,

If you can afford it then a RDF is the answer for pre-filtration.

As Manky says the baskets would no doubt work better planted but I've had mine in the garage for 4 years without any plants. I imagine these fancy LED lamps work well but they seem to cost a fortune to purchase. I might well try one myself as I'm planning to turn the current filter into a quarantine tank and create a new Anoxic filter outside with plants.

Lift the baskets off the bottom in your filter (plastic pipes) so that the water can flow all around. Don't forget some sort of defuser. :D
Post Reply