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  1. hi samatuer, I have had the same thing happen to my tandanus cat fish. Do they have tiny white spots on them? Although they should survive without heating the water in those sort of temperatures, they just don't seem to in captivity. I have an electric heater in with mine to keep the water at about 18 deg over winter and have insulated my tanks. Also how often are you feeding them? When it's that cold I wouldn't feed them any more than maybe once a week, and even then only a small amount that they will eat straight away. cheers, Andrew
  2. G'day Brownie, I have insulated my IBC tanks by putting a layer of fiberglass around the outside, and then filling the gap in between with expanding foam. It works a treat, but as you mentioned, the expanding foam isn't that cheap (especially since i brought it in those pressurized spray cans). However, I believe you can by it in bulk and mix it up yourself; it's used to fill the gap under boat floors to provide buoyancy.
  3. Hi Guys, ...I'm certainly not the expert on air lift pumps. I have only experimented with using various pipe diameters, with/without air stones etc, whilst keeping the air pump the same. I noticed that when I optimized the pipe diameter for the best water flow rate, the air lift pump became more susceptible to the tank level dropping. I.e. even though it moved lots of water at only a few centimeters of head, as soon as the tank level dropped even a small amount, the water flow stopped. However, by making the pipe smaller (25mm --> 20mm) the air lift pump would move slightly less water, but operated more reliably as the tank level dropped. From memory my pump was moving about 500 L/h using only 6 W (albeit at 50mm head). This is why I went down this path. To realistically run an aquaponics system on solar/low voltage, the power consumption needs to be very low. To run say a 50 W pump continually you would require maybe 150 - 250 W solar setup, as here in Melbourne in winter we may only get 3 - 4 effective sun light hours a day. I'm optimizing my system to run off a 60W solar panel, so I'm trying to keep the power down to ~ 12 W - not easy! . Hi Phri, regarding efficiency, I was thinking more along the lines of system efficiency. I have a solids/biological filter that sits inside my tank just above the water level, in an effort to minimize the required lift - thereby minimizing the power required. Bazza, I haven't tried using compost or anything else to heat the tank, but I have always wanted to give it a go - it's somewhere on my to-do list! I've also thought about using a home made solar water heater - but I just haven't tried it. Also I'm a bit limited in space. I have all this setup in the very small backyard of my unit!
  4. G'day, Ye I probably shouldn't have used the word 'impossible', I have seen an article in an alternative energy mag, showing them being used to lift water out of a bore. But they used high air pressure from a normal air compressor. I did a but of experimenting with mine after finding an excel spreadsheet on the 'net with some formulas for calculating water flow vs air pressure and depth etc. As a general rule, it seems thinner pipe, higher air pressure, and greater submergence will give greater lift. But it also becomes less efficient. At the moment I have 2 IBC tank setups. In one I have 50 tandanus and silverperch (they are only little). In the other I'm running 15 rainbow trout. Keeping the trout through summer has been a bit of a struggle, but Im slowly leaning when I need to chuck some ice in the tank QUICKLY! I've changed the flood/drain times and with a few more mods I think I'll have some success with the trout. If it is all OK, i'll gradually change over to trout - the cost of heating the water for the other tank is getting crazy. How about yourself?
  5. Hi Bazza, I think those pumps use brushed-type motors, so I think they may wear out just like the Rule bilge pumps do after a while - but I'm not 100 % sure. I think it's almost impossible (or at least impractical) to use air lift pumps to pump water to that height. They seem to work best when they only pump to about 10 % of the depth they are submerged. I only use the airlift pump to run my filter which is mounted inside the fish tank just above the water level. But I figured that not only will it pump water, but it will aerate as well.
  6. Hi Bazza, All the ones I used had a fairly constant current - unlike the one you have. However, I had one just yesterday that all of a sudden went from ~350 mA to 1.2 A! It's still working but not pumping as much water. I have only ever used 12 V in my system, however I have had much the same trouble as you - the stuff made in China is just not reliable. There is no theoretical reason why a 12 V system shouldn't work just as well as a mains powered one, but quality pumps just aren't available. So, I have moved away from trying to pump water and have started using air lift pumps. I'm very slowly working on making a good 12 V air pump based on normal aquarium air pump diaphragms, but re-engineering all the inside bits (valves etc). In the interim I'm using a 240 V air pump to run my system, but eventually it will run off 12 V and solar panels. I do however use a Rule pump to cycle water through the grow beds. Although they aren't much good when operated continuously, they work ok in this application as they only come on for 3 to 5 times a day for 15 mins. I wish I had an easy answer
  7. Hi Bazza, Unfortunately things made in China often don't meet the specs listed e.g. the 2.3 A might be at no load. Is it a brush-less unit? I'm assuming with a life span of 30,000 h it must be. If it is the type I'm thinking of (something that looks like this): 2000L/H 12V DC CPU Cooling CAR Brushless Water Pump 2 Phase IP68 F Fountain Pond | eBay I have used them a few times. I have also had a lot fail in 12 months or less. But I also have one that has been running for a couple of years with no probs. They seem to be OK as long as you don't use them to 'suck' through the filter etc. Otherwise they heat up and stop working. They have some electronics inside them to convert the 12 VDC in to 3 phase AC. The impeller has a magnet on it similar to a normal mains powered aquarium pump.
  8. G'day, Initially I tried fly-wire screen scrunched up. But it didn't work very well. It seems to be more important to not impede the air flow too much - I guess the fans aren't very powerful. So in the end I used the open filter mat stuff that I use in my filters. I roll it up and push it down the tube, leaving the center open to get plenty of air flow.
  9. G'day Bazza, I'm surprised to hear that the current increases so much to your pump. What sort of pump are you using? Also, what is the voltage when the pump is drawing 4.5 A? I'm guessing it is relativity high - maybe 14.5 - 15 Volt?
  10. G'day, I have finally tried out the cooling tower and taken some measurements. it seems to be working quite well after some experimenting with the packing inside the column. I'm using two computer power supply fans and a small brush-less water pump rated at about 5 W. The whole setup uses 12 V. Ambient Temp: 27.7 C Water Temp: 24.5 C Water output: 23.9 C (output from tower) As you can see I'm getting 0.6 C temperature drop. After moving the packing around a bit I managed to get 0.8 C. After the cooler has been running for a while you would expect the tank temperature to approach the wet-bulb temp (which was about 19 C at the time). Cheers Andrew
  11. Hi guys, Thats great to see you have got some silver perch out of your system ColinW - I thought it may never happen ! Matt, I'll take a pic of the cooling tower and post it over the next couple of days. As an example, theoretically (Dewpoint and Wet-bulb from Relative Humidity Calculator - Weather Calculators and converters - 4WX.COM ? Weather Information Center!) at a R.H of 45% and an ambient of 25 deg, it should be able to bring the water down to 17 deg. I figured if it works, I can switch it on when the conditions are right and help buffer those really hot days. Now I just need to get it to approach the theoretical limit - which will probably be difficult. Although evaporative air conditioners work OK'ish in Melbourne. If nothing else, the water trickling down the tower will increase the oxygen content of the water. cheers Andrew
  12. G'day Guys, thanks for the replies I guess I should think myself lucky that I only lost 6 out of the 20 trout when the water temp got up to 26.5 and they should only have survived to 22. I think the idea of increasing aeration may be a winner as well. Most of the heat is coming in through the grow beds as the tanks are insulated. I have change the times when water is cycled through the grow beds, and i'm currently making an evaporative cooling tower out of some 100 mm PVC pipe. Hopefully this combination will keep the water at a trout friendly temperature. cheers Andrew
  13. G'day everyone, I'm interested to know if anyone is successfully producing any fish in Melbourne out of their system. I have been doing this for about 3-4 years now, and so far no fish have actually been harvested. I have 2 setups using IBC tanks. I started out with Tandanus catfish and silver perch in both. However I was getting a bit 'over' the electricity bills to heat the water during the colder months. I know the natives should survive without heating but then they don't grow and are prone to disease. After I lost all (25) in one of the IBC's to white spot, I decided to go for rainbow trout - I really wanted to get rid of the heaters! I still have catfish and silvers in the other one. However, with the 40 deg day yesterday I have so far lost 5 trout. I guess I'm just wondering if maybe I'm trying to achieve the impossible. Is anyone in Melbourne - or somewhere with a similar climate (i.e. 40 deg one week then back down to 14-20 the next) actually able to keep fish alive without resorting to expensive heating or cooling of their tanks? Sorry to sound a bit negative - but the dead fish are very frustrating....
  14. hi, I don't know of any suppliers in your area, but since you haven't had any replies, I got mine from Murray cod hatcheries in wagga wagga. I can't remember what the phone number is, and I can't find a website. They will courier fish though. Andrew
  15. Hi fishgeek, I don't use one of these air pumps - I'm trying to optimize my system for low voltage/low power solar panel operation. However, I can tell you that the VA rating on this pump is 4.3 * 230 = 989 VA, which is close to the rating in Watts. (the difference between W and VA depends on the inductive/capacitive nature of the component). I'm not sure on the cost of electricity in your area, however here in Australia: ~22 c/kWh if you run it continuous and assume W = VA: 0.22 (rate) * 0.989 (kW) * 24 (hours) = $5.22 per day. The air pump I use runs of 12 V and uses about 6 W. I use two of these in my 1000 L IBC tanks. Hope this helps....