I’m really interested in building an Anoxic filter and have the bits ready to go but before I get started I have a couple of questions.

Firstly hello! This is my first post and was directed by Syd as I have contacted him regarding the Anoxic filter (thanks Syd for the time and info!)

I’m really interested in building an Anoxic filter and have the bits ready to go but before I get started I have a couple of questions. I’m in a similar position as 'Dave-the-koi' my pond is 1000g and I have 6 fish/Koi (2@10",1@12",1@16",1@18",1@22") I don’t think Dave really got an answer from anoxic 101 in regards to his planned 6x2x2 pond? Now I planned a 6x2x2 (11 pots?) but can squeeze 6x3x2 which should give me 17 pots? I would rather use the smaller pots but as said can squeeze the latter. In the book for a small pond it says 15 pots but also says 1 pot per fish and I only have 6 fish so do I go for the 6x2x2 or 6x3x2?

Probably a silly question but if I have a 1000g pond and put an Anoxic pond on at 225g is my pond 1225g as I have heard different things about pond calculations including excluding filters, daft as it sounds, flow rates, I was planning on a Superfish 8000 from the 5000 I’m running now, it will be returning through an electro heater so not sure what I will get but would hope for 1300gph I doubt that will be enough?

I understand diffusing the water inlet but how about the exit? Is it a simple open tank connector or does that require like a pipe with drilled holes in?

I have some iris (I think) in another pond that’s established and in urgent need of repotting are these good to use? Or a bit too much as there 3 foot!



Thanks in advance!

First let me say HELLO ALEX1977 and thank you for coming on this forum (KKU) for help. In answering your question about Biocenosis baskets sizes and/or Anoxic filter size: There are hobbyists that do decide to go a little smaller on the Biocenosis baskets only because they (the baskets) are easier for them to handle. As you may already know, if you plant a Lotus then bigger is better but then there is a tradeoff of weight verses size. So a smaller filter can accommodate more baskets if you use smaller ones:

9"X 9"X5" MEDIUM

18"X7"X6" KIDNEY

11"X11"X7" LARGE

Always try to accommodate as many Biocenosis baskets as you can, it will give you the biological insurance for future growth of your animals’. Don’t be surprised after cycling of the Anoxic filter your Koi become perceptive of their food than before the Anoxic filter. No one can predict what the animal load will be in two years from now so more Biocenosis baskets are always better. The number of fifteen Biocenosis baskets (11"x11"x7") that I mentioned in my book is what I would call a minimum for most ponds. All I’m trying to do here is give the hobbyist some kind of guidelines as too how much they should use for the average pond. Always keeping in mind that you can add more baskets latter as needed.

As far as flow rate goes once again try what you have and if the water turbidly suffers then you may need a higher output pump. Once again this will be a judgment call on your part and if the parameters of your main pond are the same as the Anoxic filter. Most of the time turbidity will suffer if pump output is too slow. You’re the one that has to look at your pond day in and day out so it’s up to you on how clean and clear the water looks.

 Also when you add an Anoxic filter onto your existing pond the filter now counts as total gallons of the pond even though the Koi are not swimming in the filter itself. For example if you have a 1000-gal pond and add on a 1000-gal Anoxic filter you now have 2000-gal pond because all pollution is now half of what it was. The Koi maybe only swimming in 1000-gals but you have a cushion of another 1000-gal for insults. It’s no different when people hook their ponds up to natural systems and pump water from that system into their ponds and back again. The larger natural pond becomes the smaller ponds filter and recirculation of new water.

When I was in college as a test we placed small fingerlings of Rainbow Trout into a large clear cylinder tube of less than 20-gals. We then pumped from a nearby freshwater cold stream its water into the tube exchanging the water 24/7. The trout were fed black fly larvae and other mayflies as an aquatic food through a small orifice in the tube in the same direction as the waters flow through the tube. The Trout grew to the point that they all were facing the currents inside the tube but could not swim or turn around any longer because of overcrowding.  This little experiment proved that fish could be tricked into believing they are in a larger environment than they really are. So the argument that every drop of water counts as pond gallons is true, even though the fish are not in every drop of water they still exist in its entire mass. So the mass of the water is always calculated into the equation on pond gallons for chemical treatment. Especially if you’re using Potassium Permanganate as a treatment and overdosing could be toxic to your animals’. Some chemicals are so lethal that treatment should be calculated by the mass of water and not by the main pond volume alone or under-dosing of the fixed quantities proscribe by the instructions can mean unnecessary prolong chemical treatment and unneeded stress to your animals.

Diffusing the inlet water is all that is necessary and the outlet flow should have no restrictions at all. The way the water is returned to your pond and its dynamics is all up to you and your Anoxic filtration build and the geographical location from the main pond.

You should plant all aquatic plants in Biocenosis baskets for optimum growth and performance without the use of fertilizer tabs. However, don’t hold me responsible when your Iris goes bonkers and outgrows the basket in one year. Iris are very prolific, because of their root structure and uptake of nutrients. I’ve seen them grow over 6' tall in one year in a Biocenosis basket; you’ve been warned!