haygar Posted September 27, 2003 Report Share Posted September 27, 2003 hi all hope some one might be able to help me i have a four foot bow front tank (300 lt) it has been set up four five week it has a hood with light under it , the light is 2*3ft tube it has three under gravel filters and a 1200l/ah external filter on only have 5 small goldfish and 20 white clouds in it about a week ago it went cloudy , my fish seem ok with that but today noticed my temp is up to 23c from it normal of about 18c must have risen over last couple of weeks summer is not even here yet and my temp is up that high what can i do to keep this down . have heard of ice blocks but is there other ways (chillers?) or such not want to spend a fortune or put ice in every day cheers hope someone can help me haygar 8) Quote Link to comment Share on other sites More sharing options...
Caryl Posted September 27, 2003 Report Share Posted September 27, 2003 The cloudiness is just an algae bloom, very common in a new tank. With a bit of luck it should clear again by itself. Any plants in the tank? These will help. Don't worry about the temperature, it is not too much for the goldfish. Over summer if it rises too much, fill some 2 or 3 litre plastic juice containers with water and freeze them. They can then float in the top of the tank and bring the temperature down. As they melt you put them back in the freezer to refreeze. Chillers are available but are very expensive. By the way, welcome to the fishroom Quote Link to comment Share on other sites More sharing options...
Warren Posted September 28, 2003 Report Share Posted September 28, 2003 Here are a couple of DIY options but they require a little technical knowledge. 300L is quite a lot to cool using ice. I have trouble keping my 1200L tank at 28'C in summer. It easily gets up to 34'C if left alone. Right now its at 30'C because we've had a hot week. Summer is not even here yet. It takes 25 bags of ice to cool the tank from 32'C down to 28'C. I used to use the water I feed to my RO unit to ccol the tank. I plumbed in a stainless steel coil of tube that sat in the trickle filter. It worked as a simple heat exchanger. Now I've moved and the RO is not suitably placed to pumb in anymore. I'm now looking at using Peltier devices to cool the tank. The peltier devices will be mounted to an aluminium block with a stainless steel tube running through it. A heatsink and fan mounted to the other side of the peltier's will get rid of the heat. Water from the tank will circulate through the stainless tube to get cooled. I calculated 300W of peltiers will be required in the peak of summer to keep the tank at 27-28'C. You would need a similar sized system (maybe only 200W) as your temperate differential is much bigger. It will cost about $500 to make this system. Its still a lot cheaper than importing a chiller, but not cheap. The other great feature is in winter the polarity can be reversed on the peltier and used as a heater. The bonus here is you get a 2:1 heat ratio, ie 300W electrical energy in, 600W heat energy out (approx). How Peltiers work: Essentially a peltier has two sides usually made from a ceramic material. One side gets hot when you pass electric current through it and the other side gets cold. If you change the polarity then the sides that get hot and cold swap. Quote Link to comment Share on other sites More sharing options...
Ira Posted September 28, 2003 Report Share Posted September 28, 2003 Peltiers are cool. Ok, so it's not really helpful or anything, I just couldn't resist. Quote Link to comment Share on other sites More sharing options...
spent Posted September 28, 2003 Report Share Posted September 28, 2003 Yeah peltier thermoelectric coolers are cool, but they don't actually cool, they just move the heat from one side to the other. You'd still be limited by the rate you could cool the hot side of the peltier, which would be the heatsink's C/W rating. And if you were drawing 600W thru 300W of TECs, you'd want a massive surface area of heatsink fans. Even in terms of high quality computer CPU HSFs you'd need like 10 of them. Wich would then need to be mounted to a large copper heat spreader plate, to distribute the heat from the small TECs to the big heatsink setup. Sure you could use the peltier as a space heater in winter, but why would you want to freeze your fish? Remember that heat dosen't come from nowhere, you're drawing it out of the tank water. The best way I can think of, short of refridgeration, is a radiator to pipe the water through. I suggest an old automotive one (or more) from a scrap dealers, as they're cheap, reasonably compact, and effective. Then get the largest, slowest moving fan possible to mount in front of it. When it comes to fans, Nigel is the man... http://www.trademe.co.nz/structure/show ... ember=7527 If you're not the DIY type, something like this might be more your thing. http://www.pcgear.co.nz/code/products.a ... bcatid=260 And if space is an issue, there's extremely efficient and compact radiators built specially for computer watercooling setups. The cream of the crop is the "Black Ice" series by www.hwlabs.com. They're a bit pricey though. Still, their top of the line model is only about NZ$170, apparently can deal with 900W of heat, and is only 153x133x45mm. The good thing is they have standard 12.5mm inlet/oulets on them, as they're designed to be used with regular aquarium pumps and tubing. Quote Link to comment Share on other sites More sharing options...
Caryl Posted September 28, 2003 Report Share Posted September 28, 2003 Something we might be trying soon. My brother has one of those open chillers they have behind the bar to store bottles in. We thought we could pump the water through it and back into the tank, using the chiller itself as a tank stand so the tank sat on top of it. Haven't had a close look at the chiller yet or measured it. Might be too big. Quote Link to comment Share on other sites More sharing options...
Ira Posted September 29, 2003 Report Share Posted September 29, 2003 Caryl, the cooler wouldn't be too big, your tank would be too small.:Þ Quote Link to comment Share on other sites More sharing options...
Caryl Posted September 29, 2003 Report Share Posted September 29, 2003 :lol: @ Ira. Actually, it is finding the space in the house that is the problem. Quote Link to comment Share on other sites More sharing options...
Warren Posted September 29, 2003 Report Share Posted September 29, 2003 Yeah peltier thermoelectric coolers are cool, but they don't actually cool, they just move the heat from one side to the other. You'd still be limited by the rate you could cool the hot side of the peltier, which would be the heatsink's C/W rating. And if you were drawing 600W thru 300W of TECs, you'd want a massive surface area of heatsink fans. Even in terms of high quality computer CPU HSFs you'd need like 10 of them. Wich would then need to be mounted to a large copper heat spreader plate, to distribute the heat from the small TECs to the big heatsink setup. Sure you could use the peltier as a space heater in winter, but why would you want to freeze your fish? Remember that heat dosen't come from nowhere, you're drawing it out of the tank water. Of course they cool. Removing thermal energy from a mass is a pretty good definition of cooling. The heatsink required is not that big (approx 150 x 150 x 200mm) with a 150mm fan running at 50% spped will do it. The heatsink mentioned will dissipate 600W with 30'C rise so no worries, - no heat spreader required either. Heatsinks are not a problem. They are readily available for well over 10kW with 40'C rise. The peltier is not used as a space heater in winter. By reversing the polarity on the peltier it works to heat the tank by drawing energy out of the air and adding it to the electrical input energy. You just need to make sure the heatsink is outside so it does not cool the room. Quote Link to comment Share on other sites More sharing options...
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