Mark McMurtry

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About Mark McMurtry

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    Senior Member

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  • Skype
    upon substantive (compelling) request

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  • Biography
    Past tense, then over the top
    All is Now. Then is Not.
  • Interests
    staying alive, integrity, canine companions and music, in that order

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  • Location
    Bozeman Montana

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  1. I've waited for you - or anyone else - to acknowledge/respond to my 'comment' (suggestion) made on Wed. - either pro or con. If/since/when people don't appreciate/want my input - okay - fine. How anyone can 'think' that they're filtering fish wastes where there are not any fish (or feed) is 'beyond' my understanding. As too is the vast majority of what has transpired here (and not) over the past 2.5 years.
  2. In Aug 2014 KellenW wrote: Posted August 1, 2014 · Report post I'll be doing a very small scale trial of iAVS as soon as I get the new greenhouse finished. I owe Dr. McMurtry a great deal of gratitude for reviving my interest in it. Some of the things I really like about furrowed sand beds, and the iAVS method in general: - Greater nutrient capture/utilization. Not just nitrogenous compounds, but all the other essential, and frequently overlooked nutrients required by terrestrial vascular plants... it's pretty rare for any system to be terribly deficient in N, and if it is, it's simple enough to fix that. It's the "other stuff" (trace elements and micro nutrients) that are often deficient, and iAVS is focused on fully retaining them to the greatest extent possible. - Relative simplicity in build/assembly. Plumbing, pump and other requirements are drastically reduced in iAVS, as demonstrated by Mark. - Reduced costs of build/assembly. Again, reduced plumbing, pump and other requirements, which potentially saves a lot of money. - Reduced energy requirements (possibly significantly reduced) relative to most other AP "methods". - I'm also well acquainted with the benefits of sand as a biological filtration media in an aquaculture context, and have designed, built and used sand filters for most of my life. It just works, and works very, very well. Some things I still wonder about, and that also compel me to try iAVS out myself: - How well will the sand beds continue to perform with a significant amount of solids over a prolonged period of time (mainly, will bio floc and sludge accumulation present any problems over time)? - How well will the furrows stand up to flood/drain cycles over time? - How will I keep the sand where it's supposed to be and not travelling where it shouldn't be? - How will maintenance and labor requirements compare to other methods? - Will biological oxygen demands be a limiting factor in any way regarding sand bed performance? - I advocate against running any AP system without pre-filtering the grow beds SO I like to challenge my own biases/beliefs, and this will certainly do that, and it seems to me that the iAVS method has excellent potential to be the "one kind" of AP system that may not require the requisite pre-filter to run in an optimal fashion. Then again, it may also benefit from pre-filter too (filtering solids and dosing back the nutrients in a controlled fashion). Who knows. I'll try both, and compare side by side. Should be fun and extremely educational for me. I'm looking forward to it. Thanks again for sparking my interest Mark! Take care of yourself, and I hope to see you around again. You're alright in my book. ++++++++++++++++++++++++++++++++ SO ... How's that going Kellen?
  3. BTW Jeff, You may or may not have a 'problem' with your sand selection. First solve the 'problem' of no fish (no particulate 'wastes'). Its amazing (to me) just how fast feces (especially following mastication via a pump impeller) can clog anything deemed to be filter. Microscopic particles lodge between surface sand grains (starting at the very bottom) and this facilitates lateral movement of the water down the length of the bed (when level). I've always 'had' - and fed - the fish from day one - with at most an inoculation a few days prior to adding the fish by dosing Fritzyme 7 and ammonia. From the first day (feeding), water went the length of the furrows (up to 6 m long) in mere minutes, then the furrows filled and water largely entered the sand laterally (into side slope of furrows). What happens next (in/to the furrows) is a different chapter ... BTW, this same longitudinal, then lateral water transport to crops also applies at vast scale, such as lettuce fields in AZ large enough to see the curvature of the Earth on the horizon.
  4. No offense intended to you or anyone else ... but I'm done attempting to define/explain sand and related performance criteria/variables.. I just do not know how to communicate in a manner that people can seemingly understand. I'm SO very weary of this. At times it appears to me the at least some if not most people just refuse to think and/or understand. Not saying this is true in your case, yet I still do not know how to communicate. I never had the slightest problem sourcing sand (in the US or in Africa). Not claiming that everything I sourced 'worked' exactly the same ... I knew what was too fine an/or too course just by looking at it, playing with it in my hands, by making 'careful' observation. I suggest that there is NO substitute for first-hand experience - while paying close attention to what 'behaves'/performs as desired and what does not. Doing is learning and vice versa. As I understand, you are aware that your media is far coarser than I've trialled. Then how can it be any surprise that it does not behave/perform as desired? Too fine won't drain well, too coarse won't saturate - duh. This is SO basic/fundamental to me that I apparently can't seem to describe/explain it. I used/recommend what I've defined/described repeatedly every way I know. The ATSM C-33 specification (US) 'worked' performed spectacularly for me. This specification is used throughout the world (by different terms in various countries) to make structural quality concrete, whether in the US, Oz, China, Egypt or anywhere else. It is not expensive or at all difficult to source - IMO. It has clearly defined criteria such as NO carbonate or salts or silt and defined particle size distribution limits. If you get material that meets this specification (not all vendors are competent, honest or knowledgeable but most who quarry for commercial contract work are) then it should work just fine - it always did for me. I'm not claiming that it is the ideal - no one actually knows what the "ideal" is. No one also knows what the limits are - how far one can deviate from what I tested/used and still achieve an adequate result - however defined. I know that I had absolutely NO problem whatever in sourcing or using sand that performed - more than adequately. I obviously DO have a problem communicating. At this point, I'm SO sick of trying to 'define'/explain sand that I admittedly get angry (profound frustration) just 'thinking' about it. iAVs was 'about' people who needed a better/more reliable diet being able to accomplish/provide more security/vitality for themselves then they otherwise could in constrained circumstances/environments. It is and never was about technology, equipment, hardware or devices - its biology and 'common sense' (which is obviously NOT common), and also not magic or woo-woo or 'technology'. I'll get off my soap-box now by concluding that it categorically amazes and shocks me that many if not most people seem to have grave difficulty understanding any of this (IMO in too many cases deliberately) and that at this juncture I feel it is now up to others to attempt to explain/describe the nuances since I am provably not able to do so. I'm not suggesting that I want this to be the case, just that it is apparent - at least to me - that this is a fact. How/why this is is open to conjecture and speculation - as is EVERYthing else wrt AP fantasyland IMO - is unfathomable to me.
  5. Welcome (not really) to the Fourth (and Final) Reich. The Four Horseman are saddled-up and the barn doors are fully off their hinges. The inmates are now in full ‘control’ of this asylum. Read a year or so ago that all or most of the Joint Chiefs of Staff and other senior military in the Pentagon had declared/pledged that if ‘Orange Hitler’ was ‘elected’ that they would all resign their commissions en masse. False Bravado much? Even though I’m a Vietnam-era veteran and a pacifist, I’d actually prefer an actual military coup before inauguration day. Wondering if these arm-chair warriors have ANY gonads at all. And here I had thought that the entire purpose of the ‘greatest’ military that the world has ever seen was to protect the nation against tyranny and oppressors - i.e., “… to support and defend the Constitution of the United States against all enemies, foreign and domestic … ”. They’ve all sworn a solemn oath to that effect. Now we’ll see if they meant it or if they’re just decorated chicken-poo self-serving lying hypocrites writ large - or not. BTW, any and everyone who may have actually voted for this moronic megalomaniac monster is my mortal enemy. Any and all sane primates remaining must rise up as one against wanton insanity, national and global suicide immediately - albeit I'm fully aware the americant's (sic) are far too greedy, scared, self-deceived and cowardly to do anything of the sort..
  7. 15 minutes - first time, every time
  8. This "side-show" is no way a temporary phenomena. It's not some anomaly or a bug. It's a feature - by design. The mental midgets and hate filled fear-freak monsters deliberately provoking the "bizarre"circus of hate obsessed "deplorables" now terrorizing the nation (and ultimately the world at large) are a permanent feature of the US and these 'dark' forces have now been deliberately unleashed - IMO. They are not only not going anywhere but will become increasingly more problematic by the hour, day, week and year(s). IMO, this is a permanent and now rapidly escalating condition provoking an accelerating vortex of angst and despair in thoughtful people. You can't fix stupid and you also can't be unaffected by a pandemic of wanton insanity. Some significant fraction of the US actually "want" apocalypse - literally pray for 'their' Armageddon - and IMO this has become a self-fulfilling prophecy. Duck and cover and/or lock and load. Sad, SO sad ... but true. The feces have already been deflected by the revolving impeller and the resultant trajectories will impact on ALL of us - assuming they haven't already impacted. Regardless of who so-called "wins" ALL of us loose. The one true statement that Ayn Rand ever wrote is "You can avoid reality but you cannot avoid the consequences of avoiding reality." The Grim Reaper is smiling, 'his' future is so bright he has to wear shades.
  9. "Remember that adequate water needs to be available to the full rooting depth of your plants and beyond (figure 2-10). If you only allow water to seep through to the top few inches of your soil, root growth and overall plant growth will be stunted.” Obviously, water in a sand bed penetrates the entire depth - repeatedly- and at no time is water unavailable to the plants - nor is Oxygen restricted Picture and the above quote is from a book "Pests of the Garden and Small Farm" by Mary Louise Flint, page 17. In a ‘typical’ in-ground garden - demonstrably NOT applicable in other media. I found the mentioned scale representation very interesting. The recommended filter depth of one feet (0.33 m) now looks a bit shallower from this comparison. Also, if plant roots grow that deep, I think more depth in sand filters means good news on many fronts. Any thoughts? Plants will develop only as much root volume as they need to support the aerial mass, not more than they need. In NFT and other various “hydroponic” techniques, plants do just fine, often far more than fine with only a few centimeters of root depth available. One should not extrapolate what is typically found in one circumstance/media to their requirements under entire different conditions. And I’ve never said that a greater filter depth couldn’t have some potential benefit, nor have I said the 1/3 meter depth is mandatory for every species of interest. It’s what I trialled/documented and it provided more than adequate rooting volume for even large tomato plants. Its what has been proven to be at least adequate for good results - therefore this my baseline recommendation (not a prescription). If one wishes to increase the sand bed depth beyond what I’ve suggested, then I can think of no good reason not to do so other than the additional cost and/or work involved. Whether or not said additional cost/work has a discernible positive impact on your productivity remains to be anecdotally demonstrated much less clinically established. If one lives enthrall of shoveling sand, then have at it. If testing bed depths - one against another - then do a ‘proper’ experiment (which is not a one-off trial).
  10. If what you 'really' want is "both worlds", then do both ... separately. I makes no sense at all to me to compromise both without any possibility of improving either. In addition, if you did both, you could compare each to the other. If you bastardize both you can compare neither.
  11. "There were some nutrient deficiencies seen at the first 30% portion of some filter beds (on the inlets side). Operators tend to make downward slope at the top surface (for the water to flow and reach the other end quickly). Lesson learned is that this is not recommended to do so." I have stated level furrows for this very reason - uniform distribution of the ‘wastes’ (nutrient) along the bed length. —————————- “The pH has been stable at around 7.2, it never went above 7.4 and we found it hard to bring it down (naturally) further.” There MUST be a substantial carbonate source in that media if pH won't come down even with all the ongoing nitrification happening. Which sand source/type is used in this project? TMK, if you can get/keep pH in the 6.0 to 6.8 range you’ll experience much more vigorous growth/better yield. And NO nutrient deficit issues. ALL growers know that pH is important for plants to perform their very best (assuming all other needs are met) - rather akin to Oxygen levels for athletes. ———————- “We do periodical events of compost tea sprays with goals to suppress some foliar pests and diseases. It is helping.” two random articles of foliar nutrient application and effects. Presentations/2009/2009 Forum Proceedings/Derrick Oosterhuis.pdf ————————- "This video shoot was done recently when most of our Arka Rakshak tomatoes were at the last leg of harvest. FYI that we are dropping Arka Rakshak tomatoes.. mainly because it is not considered organic and thus has less organic market demand/premium prices. While yields have been consistent with hybrid seeds, there are less takers in the organic market. Future is for heirloom vegetable varieties we would be focusing on. That is a new lesson recently learned." Still unclear whether those were the Arka Rakshak cv. or not. The comments about F1 hybrid seed not being considered “organic” is ‘news’ (novel aka strange) to me. Obviously, regardless of ‘reason’, you should grow what your market wants. However, with “heirloom’ varieties, be prepared to cope with disease. Pests are a different subject yet can also function as effective disease vectors in addition to the direct damages. ——————— Still very unclear why my repeated suggestion that you trial the single-stem cultivation technique with tomato is ignored and remains untested. Do you have some ideological prohibition against (theoretically) “injuring” the plants? If so, proper pruning does NOT injure plants, it ‘helps’ them ‘be all they can be’. Just ask any professional grower, or arborist or vintner. Please don't take my input/questions as negative. I'm trying to help - everyone. Albeit that doing so typically produces angst, conflict, distress and/or backfires.
  12. 1. No such thing as "perfect". 2. Everyone's circumstance is different (environment, resources, ability, expectation, etc.). 3. What is your response (as based on experience) ? - assuming that you have. 4. Personally, at my age, location and health status, the "perfect" system is the one that I do not have (= none). 5. Personally, if I was 40 again, the "perfect system" would be to operate one or more of every so-called technique still being hyped at light speed so that direct side-by-side real-world comparisons can be demonstrated/documented with the purpose of winnowing all the chaff from the grain (aka manure from the meal).
  13. 1. I'm presuming that this post with eventually get past the APN gate keepers ( and also be ignored by the resident trolls). 2. I saw your video post, went to YouTube hoping for a translation and found none. I (and likely few others) have your multilingual skills. We would be substantially benefited if a closed caption version and/or other other means of translation was made available for this and future videos. 3. Gary and I spoke of your video on Skype yesterday. We are both well impressed by your/their efforts - again. 4. I looked with care and saw absolutely no sign of any potential nutrient deficiency in the plants. This prompts me to inquire as to what the pH being maintained in that 'system' is (range) AND whether or not you/they are or have added anything (nutrient source) other than via the fish feed? 5. BTW, the tomato variety there did not appear to be the same cultivar as in your recent trials - and I have also not seen an photo of any of your trials being grown as a single stem (in the US and Europe this is standard practice as if provides the greatest yields per unit area/time). Is there a logistical reason you choose to not trial this cultivation practice? 6. I can't 'speak for' anyone else, but I would be very appreciative if in addition to your photos and video posts that you also included operational parameters and performance data as available. For example, what is the irrigation schedule used and volume (or % of tank vol) moved per event, number of tank exchanges per day, feed input rate (averaged over a 3-4 month crop cycle), et al. 7. Are your brother and/or other clients finding that their efforts are making economic 'sense' - aka, are worthy of their effort, recouping cost of development in a satisfactory timeframe, etc.? In other words, after having gained first hand experience with the technique, what are the operator's assessments/level of satisfaction. Have their expectations been met and/or exceeded? Sure, this may have been indicated in that video but it is impossible for me to determine the degree of satisfaction (or otherwise) since I did not understand a single spoken word. 8. Keep up the good work - I know you will. edited for typo
  14. Who said (asked) ANYthing about "carrying capacity"? So-called carrying capacity is always an vague open-ended moving target due to "too many variables". The question posed has ZERO variables. The question presents 2 sets of 3 'data points - NONE are variable.. The answer is arithmetic. This is not a multivariate calculus question. Its a straight forward, no trick, no gotcha simple arithmetic problem that any Chinese 3-rd grader could answer in under 5 seconds. So, when you were in 3-rd grade and the teacher asked what (10 - 2) divided by 2 was, did you get extra credit for claiming "unknown, due to too many variables"? I didn't think so. Your grade on this week's quiz is 0%. Class dismissed.
  15. Anyone 'care' to disagree with MT Mind ? ... other than OP that is.