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Thread: Efficiency of Nexus bio

  1. #1
    Sansai
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    Efficiency of Nexus bio

    As a relatively newcomer to koi keeping, I followed a recent thread making reference to types and styles of biofilters. With no history or prejudices in this hobby, I was trying to find the nuggets of gold within all the drama. On my first and only pond, I choose the Nexus 300s as my primary bio filters.

    I found the statements that an upflow moving bed filter being only 15% to 20% effective due to internal tracking interesting. After watching animations, and listening to other people’s logic, I started to feel less confident on my original choices. Although I must confess that I have never had a trace of ammonia appear in the pond in my short 2-year history of keeping koi.

    This morning, I wanted to add koi clay to the pond and remembered the “test” that was recommended to prove the logic of tracking. I started to make a gauze-covered framework that I could sink into the top layer of the bio section so that I could view the tracking for myself.

    But as I began thinking more about this “test”. I realized that koi clay, dyes, and other such substances are not removed by a nitrifying bio filter. The ability of an aerated bed to self-clean means the clay would just flow past…therefore this test would only prove that the media was not holding onto the clay and nothing to do with the mixing of the water. An example would be filling an empty bucket with muddy water, using a stick to stir it completely and thoroughly, then run new water in while draining from an outlet pipe. There would always be darker staining near the output because all the mud would have to pass through a smaller opening. This would be a more viable test if the media removed mud or you used something that the media removed… but unfortunately, you can’t see ammonia or nitrites to visually prove tracking.

    Then I realized what a simple (farmer mentality) test could look like. I took four samples of K1 and biochips out of each Nexus… one from each area around the circumference. I put the 8 samples on a white board to compare them. There is absolutely no difference in the color of the biofilm on any of the samples. Since the biofilm color/thickness changes based on the amount of food that it receives, I’m now thinking that the food is being equally distributed throughout the containers. Even if some “tracking” occurs, it is not substantial enough to affect the overall performance.

    I’m not concluding that other filters aren’t better designed or that I couldn’t build a better mousetrap myself because there are strengths and weaknesses in every filter. I can only say that using my somewhat unscientific test, my Nexus filers’ bio capacity seem to be operating at a much better efficiency rate than the quoted 15% or 20%. If my logic is wrong, please tell me but let's not start another thread like the last one.

  2. #2
    Honmei KoiCop's Avatar
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    Hello Steve . . .

    Pretty darn good insight if ya ask me.

    (Wonder what that renowned French physicist will think about your bits dancing around in aerated stagnant water whilst trying to grab cheeseburgers from cars passing at 130 mph? )

  3. #3
    Daihonmei
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    well, here's a quote you have to believe ;

    "No doubt, the very best way to filter this pond is by way of purchasing two Nexus 200 filters from Evolution Aqua and link each of them up to the two outlets from your central diffuser bottom drain. "

    Now that's a pretty strong endorsement. But since you've asked not to tear up your post with drama, I'll leave it there.
    If you'd like to know more about that quote please do see my post/thread in the 'outside' section entitled " seeking the truth"--
    I now return you all to this normally scheduled thread---
    Happy koi keeping!

  4. #4
    Daihonmei MikeM's Avatar
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    Steve: After 4 and a half years using Nexus, I do not think you could better. They are not as simple to maintain as the marketing suggests, but not too much work. Any number of filters can be as good in a particular application, but no regrets here.

  5. #5
    MCA
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    Honmei MCA's Avatar
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    After 4 years + with two Nexus, I converted from 410 Answers to EAzy as first Nexus first stage. and added two short showers on the skimmer circuit. Gotta love that combo.

  6. #6
    Oyagoi Lam Nguyen's Avatar
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    Howdy Farmer! Excellent observation and yes, I agree that there are strengths and weaknesses with every type of filtration system. Regarding your observation about taking four K1 chips from four different areas of the Nexus, I am sure that those of us who own the Nexus system can agree with you on this one. Please keep in mind though that it's a fluidized bed and the media move can and do move around.

    As far as the 15-20% efficiency concept is concerned I also found this very hard to grasp. After all, all of the media is exposed to ammonia-rich pond water all the time which to me equates to a 100% efficiency. I have three Nexuses (sp?) and all the K1 and biochips are equally brown throughout the biological chamber. I find these media very effective as a biological media. The only thing is that it took a very long time to cycle compared to shower-type filtration systems.

    I agree with MCA that nothing beats a pond with a combination of both K1/biochips fluidized bed and shower-type filtration. I wonder if there is a need to add ERIC to this combination.

  7. #7
    Daihonmei
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    Octopus- Octopi
    Nexus - nexi

  8. #8
    Daihonmei MikeM's Avatar
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    Why are air domes are used over bottom drains? ...not to create upward current flow to the skimmers, but to create downward flow at the edges of the pond, and across the bottom of the pond. Combined with properly placed returns, the result is movement of water throughout the pond with no stagnant spots. In an air-driven fluidized bio-chamber, the multiple points of air injection create a multiplicity of up-flows, down-flows and cross-flows. As noted in another thread, the result is chaotic, continuous movement. If this is not occurring in a Nexus, check the air ring for blockage. Fine debris can build up to block the tiny holes in the ring. This can be removed with a straight pin inserted in each hole. I have very slightly enlarged the holes in the Nexus and EAzy air rings on my units by inserting an ice pick in each hole and just wiggling it a bit. I still experience some blockage, and so check it out about once a year or so.

    There is an area of low movement at the very bottom of a Nexus bio-chamber in the trough below the air ring. Very fine particulate settles in that area over a course of several months. I clean it out about once per year. It's a pain to unload media to get to the rings and remove this sediment. It is de minimis in a koi pond environment, but I am just picky enough that I don't like it being there.

  9. #9
    MCA
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    Honmei MCA's Avatar
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    Jim,

    As we know for Latin masculine nouns of the 2nd declintion the singular genative or and plural nomnative case ending do end in "i". For those not knowing Latin, nomnative case is for a noun that is typically the active subject of a sentence. Genative case is possive....which in English we should that usually adding 's to the end of nouns.

    But, we are referring to a upper case trademark name...not a lower case general purpose Latin word.



    bonitas non est pessimis esse meliorem

  10. #10
    Oyagoi Lam Nguyen's Avatar
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    Quote Originally Posted by JasPR View Post
    Octopus- Octopi
    Nexus - nexi
    Thanks JR. Will not make that mistake again. Englesh is me second langauge, so me sorree!

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