My tap water here in Wichita Kansas has a PH of 8.0. It's basically liquid rock. I'm old school and have been using undergravel filters for 36 years now. Looking forward to the results of this test.

Really bummed your first go round with the anoxic just didn't take. I have six and am enjoying them immensely. Leaving out the fact as you mentioned in your last video that I'm running full plants and REALLY never gave the anoxic system a shot as a stand alone filter. Very happy to see you rolling this experiment as a stand alone so we can all see this works or isn't as magical as I think lol. I'll definitely stay tuned!

Will be interesting to see this project progress. I was, for a while, intrigued by the anoxic filter idea, but opted for dirted deepsand largely because of the simplicity of not having any moving parts to maintain. Also, on closer study of Novak's explanations of anoxic filtration, he seemed to do a lot of rambling with scientific terms thrown in at random and in ways that appeared inaccurate to the meaning of those terms... This caused Novak's explanation of the process to lose legitimacy for me. He also had plants in all his tanks... During the experiment, it may also be worth considering if any potential denitrification is taking place by other processes such as assimilatory denitrification. Looking forward to your 'plantless' experiment 👍

If you want more flow, it's easy to tee in another air line, and put another sponge filter in at the other end of the tank. I often have several bubbling away, ready to be moved to a new tank as a pre-seasoned filter.

good work!

Great Job Bentley! Love this detail!!

Thank you Bentley!!!!

Loving this experiment thanks:) And game show prize model hand move for the filter gunk addition was perfect!

Sweet i think you will like it. I have anoxic undergravel and i followed Novac's plan to the tee but used kitty litter in the 40G , Turface MVP in the 90 G and a 60G. Going to use Saf-T-Sorb in a 180 G. Running mostly Sumps and one corner matten with a double jetlifter in the 60 G. I never see any Nitrates unless i add liquid to the water column a few times. Lots of plants. I added Laterite to my substrates though because i think that helps with the bacteria in the substrate. If you use a a canister try a BCB basket in the canister that would be cool . I have a BCB in a 20 g with a sponge filter and the Nitrates always at zero for over a year. BCB i made from litty litter. I think that Turface you are using is sucking up all of the Nutrients. Thanks for your updates.

I had issues with KH and PH at first, it took several months of adding cuttlebone to the tank for it to start rising. I use a cannister in tandem too. But agree a sponge is best for this experiment. My nitrates are low but not zero. I expect it will take a few more months. But plant growth has been great.

Wow I like it old school under gravel filter used that 50 + years ago maybe I was getting anxious bacteria and never knew it.

This a very interesting experiment and I am looking forward to seeing your updates on it, I am glad to see that you did not just ditched the anoxic filtration system because it didn't went as expected when you started it, my tanks are currently running a undergravel filter running slow to promote anoxic filtration, I think for me is working well, specially on my 20G tank, not so good on my 10G tank, however I don't have any cyanobacteria with this system after 3 years so that's a plus for me and it was easy to set up and zero maintenance to the filter plates, I still occasionally do water changes, but I stopped for about 8 months due to work related reason and nothing died so cool 😅

I have played with plenums and tried to make it work. If it does work, it doesn't use enough nitrate to make a difference. Good luck, though.

Hey Bro! Been keeping up on your experiment. Ive been looking over my Uncles GROSSLY overstocked 200 gallon pond. Water tests stayed at 0 NH3, 0 NO2, and 80ppm NO3, a few years ago I built a bucket filter, It did clean up the water. That pond gets very little water changes due to the fact Uncle hates wasting water. I did however plumb the filter so it would accept a garden hose to water his plants he's slowly warmed up to water changes but still very few. I decided one day (7 months ago) to plop a big bag of kitty litter along with another bag with carbon purigen and GFO in it ( I decided on GFO due to 4 ppm's of phosphate. Left bag in for 3months and removed it so now it's just kitty litter in it.) It barely fit. The 5 gallon bucket filter has 1 course sponge and 2 medium sponges along with the BCB bag almost the size of a volley ball.. I tested the water 2 weeks ago 0 nh3-0 no2 -40ppm NO3, Phosphates 2ppm. Mind you this 200 gallon pond has 7 12" Koi, and a crap load of gold fish. I'm planning on building a bog filter on the lower half of a 50 gallon drum and dropping another 5 baskets of BCB's with the extra room. I'm sold. I also have a Fluval spec 5 with 6 mountain minnows, no plants yet with full on snap together wall to wall plenum, 2 inches of litter. had that set up for 1.5 years zero ppm all across and zero phosphates. Good Luck!

Maybe run an internal polishing filter in the anoxic tank to keep it clear?

I've always found this concept interesting. We know for a fact, it's a process that occurs in nature. There's far to much pier reviewed literature to doubt it. However, Getting it to work in a small volume of sediment is a mixed bag. I've tried sand beds (with and without plenums) and 'BSB's' in planted tanks with only anecdotal hints it may have worked. I mostly thought it was a fun exercise because I had extra space in my sump tank, and I figured why not put something like this in an empty chamber and then grow duckweed floating above it for nutrient reduction and reduce my water change frequency. Yet, proving any denitrification took place is another matter all together. But, I never had it in isolation, and could never tell if it was the anoxic zone, the duckweed, or the abundance of other plants in the display uptalking it. All I knew is that I layered multiple things to develop a strong system over all. Much like in nature where theoretically any slow moving body of water can easily exhibit an anoxic zone in the sediment layer along side any macrophytes or aquatic plants, and it will also likely have a riparian zone. I wanted to mimic that. So long as there is sufficient secondary macro nutrients in the substrate, they should eventually establish (90-120-ish day seems to be a general recommendation). The question is: how much of an area are facultative anaerobes actually occupying, that are actually using an anoxic pathway? If they have to much O2, they don't denitrify. The sweet spot is the layer of sediment where free O2 has been used up, but they still have oxygen containing compounds to reduce for an electron carrier (things like NO2- & NO3-). Once you pass that sweet spot and they run out of things to reduce, they they go full anaerobic. One tip I can lend is that you can detect the optimal range by putting a OPR probe in the plenum. It may not be a nutrient related issue you're having, they may just be getting to much oxygen. A probe would rule that out. Beyond that, best of luck with your experiment. This one isn't easy to set up.

Have you ever considered just loading a canister filter with clean lava rock and adding it to an established tank with fish? While I'm not a biologist, it just seems logical that the porosity of the lava rock would lend itself to provide the anoxic conditions that the bacteria you want to cultivate. Further, the constant flow provided by the canister filter would maintain the high nitrate environment the bacteria need to thrive. Back in the 1990s, there were some articles in the hobbyist magazines of the day discussing anoxic bacteria in aquaria and how they might be able to lower the nitrate levels. I believe that it was postulated that lava rocks in a canister filter might be a possible approach, but at the time cannisters filters were expensive and beyond the means of most aquarists. Also, in the 2000s, the deBryn filter (an air driven wet-dry filter mounted inside the aquarium) was mentioned for use in tanks with larger young killifish populations to maintain high water quality and decreasing the need for frequent water changes.

Mmmmmmm That's some nice, thick, dinge. Does anyone else enjoy the aroma of filter bac? It reminds me of healthy garden soil, pulling weeds, and seeing tomato vines thrive

Ok so I mentioned in a previous video I have 5 tanks with slow moving plenums. 4 have next to no nitrates. The 5th one however is a 75 gal with larger fish and so higher fish food load. I have always had problems with nitrates in that tank. I can't use plants in the tank because they decimate them. I do however, have a few emmersive plants on the back of the tank which are doing fine. Prior to adding the plenum I used a bcb bag in the canister filter and could really not see any change in nitrates. Now i was using the api test kit and i can't tell the difference between 40 and 80ppm. I since have purchased a hannah nitrate tester for more accurate results. So after adding the plenum to this tank and using the hanna I have found the nitrates to be 50-60ppm on weekly testing. So not sure how much the plenum has made a difference because i did not have the hanna before the plenum. But it seems to be holding there, with exception of last week which was at 45ppm. I did a decent job with the plenum however I found out after the gravel size I used which was pea gravel was too large. It needs to be 1-3mm for best results. Not sure if that means my tank can't be as effecient but my nitrates are definietly not at zero. The plenum has been running for 6mo. At this point I am probably not going to redo the substrate. I may experiment will an overhead sump and bcb baskets.

so how are you going to understand, was the water filtered by anoxic layer or by sponge filter?

Here in central Florida we have bacteria that produce H2S rotten egg smell in anoxic conditions. I hope you don't get those.

I no longer use strips or liquid PH testing methods. They are highly inaccurate. Invest in a decent PH meter and keep it calibrated and take the guess work out of PH testing

Here’s what I don’t understand: if you need oxygenated water to support animal life, how could that water then be used for anoxic denitrification?

Try ash

To much work