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  1. Slow response sorry Firestone EPDM, (Pondgard and Geogard) until recently carried NSF rating, however only really valid in US and it needs to be renewed every few years at significant cost. As a result its no longer provided. Be aware of roofing versions as they can have fire retardants included. I believe plastics like HDPE still carries this standard however there are hundreds of versions and manufacturers. Each formulation should carry its own rating and tests. Similar for PVC All thermoplastics contain plasticisers and UV protectants which leach out over time. Most water supplies contain lots of these plastic materials.
  2. Have a look at these ones Run on 12 v dc so dead simple,to run from battey Can get a HUGE hopper Anything automatic needs supervision
  3. Ive used them for a few years, work well Bit tricky to calibrate but once running meter out well Can get extended or bigger hoppers for them too. I think the 12vdc version of day timers are like $10-$20 but Super feed guys have a heap of options too. I did that side myself because of different AC power here
  4. Interesting reading Good to see different ideas being thrown around and both positive and sceptical opinions count. Sand growing media in greenhouses isnt a new thing but mostly used due to ease of plant handling. Disease is a major problem in these systems. Sterilisation and media changeout is done regulalrly. Much of open field horticulture is on high infiltration sandy soils, but mainly due to sensitivity to waterlogging of the crop. Not sure production is greatly different is managed correctly but it sure is easier to manage. Sand and deep sand filtration is also ages old and considered very effective but flushing expensive requiring high volume and power requirements to do so. Effectively this concept is working to be both a growing media AND filter. The filtration side is the only key question. a few cautions from what Ive read Overstating results or making grand claims, and there are some in there, detracts from the solid basis of the concept. Also makes a lovely target for detractors, now and in the future Transferring from small trials to "moderate" or "massive" scale is a big deal, dont underestimate it. - eg. removing a few inches of sand from 20,000m2 of sand growbed is a big deal and likely to sink the concept commercially Filtration is dead easy, its cleaning that filter and making it reliable thats the hard part. Im tending to agree that this seems like a variation on gravel grow bed. Perhaps well suited to basic or sustainance type setups in certain locations. Until the clogging and change over rate of media is worked out. its destined for small home usage. Which is not a bad thing, but claims of becoming big scale commercial might need tempering Flood and drain systems were very purposely developed as one method to have highly aerated but moist root zone. Plants exchange nutrients and water at an interface where the air/water is at a certain level. Different plants need different levels. How effectively you make and keep this uptake zone, is how well it works. Some well managed but poorly conceived systems can work very well, similarly excellent setups run badly wont. Even the wrong plant choice will deliver mixed results. In reality how well this zone can be achieved and repeated over many years is the key and thats why some basic but simple systems can outperform high tech over long term. BUT dont kid yourself a well setup and managed high tech system wont do better when managed correctly. So clogging for me is a big concern, even in coarse gravel beds I have. They havent been touched in 4 years, have 2 filters upstream and still Im seeing some siltation and problems developing. Possibly large portion is from outside the AP system, like dust, leaves etc etc. My drain from swirl and fixed K1 filters dumps onto the ground, despite being very small setup there is a depression filled with fish poop silt, some inches deep, which doesnt go away or degrade. It dries out plenty and doesnt go away. Its quite smelly and not something youd want on growing surface in growbed. Weeds and pests would love it. There are some serious problems and cautions with using animal manure on surface irrigation of edible cropping. I also have issues with any AP water open to sunlight grows a tough green algae which clogs splash area in grobed and eventually blocks 19mm inlet pipes - ive covered them to stop it. If the sand media concept is good, why not use exactly as grow beds currently with filtration upstream? At least, in trial format, this will isolate a key concern and determine if the presence of solids on the surface is linked to current results or the media itself How about installing some flushing system under sand beds? high volume water can be used to move solids up and out overflow at end of season without dumping sand. Another key question in this discussion is the much agreed topic of separation of fish and plant systems to better manage both?
  5. Super feeder Just use ebay day timer to control with 12 v plug pack Might still be outside $$ range
  6. Not sure on that advice Anyone in pumping will advocate getting the correct pump for the job and buying good quality. I think the rule of thumb is a buy price of an electric pump is only 30% of what it will cost over its life. Often a margin for wear is allowed and yes maybe throttling a little when new. Assertion that smaller pumps is cheaper or lower quality make isnt correct, most make a range of pumps in lots of sizes, dont get cheaper or nastier just because they are smaller. Pumps have flow performace curves AND efficiency curves, finding a sweet spot where they all work is the key and art of selecting best pump for a job. Little stuff used for domestic and AP used probably range from terrible to appaling inefficiency but at a few humdred watts few care about this. The best pump is one running close to max flow and pressure unrestricted. Without power measurement or use curve you dont know if choking is helping or wasting energy. Do see some using 2 kw plus types and that is going to get quite expensive to run if the extra performace is choked or not needed.
  7. Throttling pump will reduce current draw to a point, also make it run at max pressure - make sure your pipes and fittings are up to it
  8. Trout grow fine in IBC Like anything need to have solids under control, plenty of air and water flow
  9. Got high quality ones from US They run on 12v and use timer to trigger set feed runtime Also rated for outdoors. Fish tend to splash and send water up into machine, need one which can handle this Seem to be a heap more around now but got doubts on quality and you will need one with few kg capacity and to handle large material - like cat feeders Aquarium types designed to handle flakes or very fine stuff. Here They are very good to deal with and will sell without timers etc. Freight is a killer
  10. Dont have to clean daily, floor of tray just builds up a bit if you dont Once a week is often enough obviously thats when fish are big Auto feeders was the other major improvement I installed, feeding 2 or 3 times a day evens things out a lot.
  11. Black material is cheap poly garden bed stuff - one roll does each IBC. its doubled up and only just now beginning to fray a little Id probably use heavier EPDM liner or similar BUT it has worked pretty well. From experience IBC arent made to last, after a few years in full sun the plastic will crack. Under greenhouse light Id say even less time. These were already reused a few times so were bit unknown. Mainly used to limit algae growth, some argue it isnt a problem but it builds to a thick layer and flakes off so I try to minimize it. I use a broom every 6 weeks or so and it is sucked out SLO, You will need a good lid and I have fences in the low places on the top as fish get out.....a lot. Im in central NSW, our winters are too cold for Barra but I did have a go with a batch last summer. Started a little late then pushed on with heating, eventually and pretty dramatically they got disease and died. Should have pulled them out smaller and earlier. Water wasnt that cool, like 12-15 deg. Even our hot summer wasnt consistent enough for them. Odd cool night and few days under 35 saw them off food. Due to cost of the fingerlings I may leave it a while before trying again. I had 20 in each tank but have run 35 trout in each before. Really need to have solids and water quality sorted and super reliable before shooting for these numbers Heating is a very difficult thing, I tried many things, gas HWS with exchanger coil was the only way which worked but was expensive. Really need to have in dual skin greenhouse AND heating to even get close to keeping it warm. Even without growbeds, tanks lost all the heat generated overnight. Another point is that Im using a fixed bed media filter too, whilst swirl types work they dont caputre it all. K1 media ~ 600mm deep does a good job. I use air to clean out then drain next day A little surprising but the 3 blue drums work pretty well. Id love a cone based drum like youve drawn but not sure its worth the cost/effort.
  12. I have similar setup and headloss is greater than your calculating. Its a difficult thing to get right under gravity. Calculators are based on having pressure to overcome some issues like trapped air. Also 25mm will clog and cant really be cleaned, you get a bioslime build up. Firstly an IBC with Barra will need 1000lph minimum EACH, I aim for 1500 lph each At this type flow it will remove all wastes well, I have used a small wave maker pump to promote swirl sometimes when fish are small. Much bigger pipe or lower flow will build up a bit, but easy to clear by increasing flow. Bypassing from top as drawn will reduce self cleaning dramatically, this is a really big deal if you cant get dirt out easily. I use 50mm SLO and 300mm mort tray, far easiest way to capture escapee's. Still needs coarse mesh until they are quite big Headloss through filtration and MBF will be around 10cm using all 50mm pipework. (plus some 110mm) This filter setup is a key flow constraint in my setup. 50mm DWV pipe works well and is cheaper than pressure PVC Always try to have pipe penetrations above water level or if it cant be then as high as possible, less head means less chance and smaller leaks also if something dramatic happens, fish will live Be aware of weight in pipes filled with water, supporting them on ground is often easiest. Fit full diameter screw caps on ends of pipes so they can be flushed and a brush pushed through. I am using gravel beds but can bypass from second pump similar to your design at night to conserve heat. There should be some old posts here on Mega bin system. Mine is upscaled version and as basics are done well it works I have altered incoming water plumbing sice these pics, I use 25mm tap now as had to equalise flows and it now arrives under lid which cuts down algae and leaves getting in
  13. NSF rating is a big problem for manufacturers even really large ones. Rules keep changing, its only accepted by a few countries and cost is substantial, its not a one off test. Expect to see less things with NSF or other ratings unless they are used in large volumes by a country and industry that demands it. Even products with NSF rating can be leaching plasticisers or other materials just below recommended limits......which change over time. You can buy 316 stainless diffusers and some made from EPDM. As others have said with the volume of biological matter in the average AP system, all of which could absorb leaching from plastics and materials Id say its unlikely to be a problem.
  14. Another key point here is resilience, lots of mistakes can be made with grobeds and the microbial and thermal mass in there does help even things out. I can see where it fits in the home market. The argument for filtration is relevant in either media or DWC as far as Im concerned so shouldnt be a factor. Taking it to flood and drain helps prevent clogging and aids aerobic growth. Most plants root activity is at the interface of water and air. Theory is flood and drain assists in increasing this area and helps support higher crop populations. Much easier to run by beginners, can be outdoors, wind etc give it few problems. DWC is a middle road hydroponics and can be pretty easy to setup and run - although Im yet to do it properly - There are some limitations to what can be grown easily in DWC from what Im told. Hydro with net pots/hydrotion is another step down the track but disease is a key problem using AP water for many plants. Things come off the rails fast too when mixes or water quality suffers. True modern commercial hydroponics is a VERY specialized business, uses high cost hybrids, heating, fogging and full automated climate control. Often rockwool slabs like Grodan on gutters are used with point applied drippers. Water is constantly fertilized and incorperates flush times to manage excesses. Water is often UV or chemically treated. Serious stuff with amazing outputs but also seriously highly strung operation. Very sensitive to disease, insects, water quality, fertigation mixes and equipment failure. Plants need lots of attention too.
  15. I have experience with very large axial flow pumps and they are a good thing BUT getting back to basics the only major difference is the placement of the motor out of the water. Problems with axial flow is the long drive shaft and possible vibration and lubrication of this shaft. A good quality submersible unit should be comparable and cheaper per ft head or gph Accurate info on efficiency on small pumps is not only hard to find but often innaccurate Also be careful as efficiencies are related to a flow rate for each pump, choking off or regulating flow output alters all this. Without proper curves and water demand, cant make accurate selection and for all pumps. This can make a bigger influence on efficiency and running cost. Kellen is on the right track getting performance data first. Allied's pricing seems very/too cheap for a good quality pump like this.