I recent ordered one of these cheap aquarium chillers from China to test on my 11 litre nano shrimp tank:
It cost me $66 SGD (roughly $49 USD, £38 GBP) delivered, which I think is a bargain.... if it works!
Seller's spec's (which I take with a large pin of salt for now) are:
- Voltage: AC 110-240V/50-60Hz
- Power: 72W
- Fit For: 8mm(Inner) Hose
- Suitable For Water Flow: 1-3L/min
- Suitable Lift: Lower Than 3m
- Size: (L)X(W)X(H) 11x11x19cm / 4.33"x4.33"x7.48"(appr.)
This seller didn't give a max. tank size, but others selling same unit have said 30-35 litres (and I've read reviews left by people with 45l plus tanks which say it doesn't do anything).
I have three of these little shrimp tanks sat next to my desk here in Singapore. The local climate is hot, hot or hot! So daytime room temp's with air-con on low are 27-29C, and at night with air-con off can rise to 30-32C. Tank temps sit at about 28-29C which I brought down to 27C with a small fan on each with temp controller. The fans work great, but evaporative water loss is a pain with such small temp's requiring daily top-ups of about 0.3-0.5 litres. (Sorry, I can't work in Fahrenheit)
First tank has my yellow Goldenback cherries (breeding!), and the second tank has my new orange Sunkist cherries (more babies!). So these seem quite happy in the higher temp. But in the third tank I have crystal reds and I've had a slow die-off from my initial 10 down to 3. All other parameters seem good, so I could only think that temp was too high. I could have increased the fan cooling, but water loss would be too high - hence I wanted to try a small chiller.
First tests in a bucket of water looked promising and confirmed that it actually worked!
I put 4 litres of warm (32C) tap water in a bucket and set it going. Temp was down to 22C after about an hour, would probably have gone lower still, but it had proved it worked / chilled / didn't leak so I switched off. Flow rate was pretty fast using the included pump through short lengths of 9mm ID tube with no flow restrictions. The water flowing back into the bucket was about 0.2C cooler than that going into chiller.
I used my multimeter and thermocouple to check the temp reading on the chiller. It seemed to initially over-read by about 1.4C, so I adjusted the temp compensation by -1C on teh controller and then the readings pretty well matched my reference as the water cooler below 29C.
So time to connect it to the shrimp tank! The tanks have a small inbuilt filter partition at the back with a tiny submersible pump at the bottom. My initial plan was to use a separate pump to circulate the water through the chiller, but I didn't have the right connections, U-bends and tubing to hook this up and I was getting an air leak into the out-take from the tank causing bubbles in the tube and a noisy external inline pump. So I gave up on that. I had a spare small submersible, but that was too big by a few mm to fit in the filter compartment (and I didn't want anything in the main tank that could suck up shrimp!). So in the end I connected the chiller inline with the existing filter pump. Water circulation speed is noticeably lower, but still acceptable. Actually it's probably much better flow for the shrimp and plants which as the original flow was a bit too strong. So this setup works well, less noise, less piping into tank, quieter and less cluttered.
You can see the two clear tubes going to/from the chiller and into the black partition at the back of the tank in the photo below:
I have set the temp at 26C at the moment, but will reduce to 25C after a day or two (just want to be sure it works reliably first!). The chiller can handle this no problem in my small (13 litre total, ~11 litre water) tank.
The chiller works well and I am pleased - especially given the bargain price (which included pump, power supplies for chiller and pump, some hose and hose clips).
The biggest problem is that the temp controller has only 1 degree steps for the set temp and hysteresis loop, even though it reads the tank temp to 0.1 degree. So you can only set the temp to 24, 25, 26 degrees etc, but that's fine. The annoying bit is the hysteresis loop which I'll try to explain: it controls how the chiller switches on and off. If you set the temp to 26C, and the chiller turned on at 26.1+, then off at 26.0, it would constantly be flicking on and off. This is really bad for compressor chillers (fridges) that the temp controller is designed to work with, but fine for solid state chiller like this except the noise of constantly switching on/off/on/off would be annoying.
So the controller has a hysteresis loop which you can set at 1, 2, 3, 4 degrees etc. The smallest setting is 1 deg which means that the chiller turns on when the water temp reaches set temp + hysteris = 26 +1 - 27C. It then cools the water down to the set temp (26C) before turning off. Then the water needs to warm back up 1 deg to 27C before the chiller switches on again. And so the tank temp is constantly cycling between the set temp (26C) and set temp + hysteris (27C).
For my tank, it seems to take about 1 hour to cool the 11 litres of water down from 27 to 26C, and an hour or two for it to warm back up to 27C again. So this gives a 2-3 hour temp cycle over that one degree range. Is that good or bad? I don't know! But I would have preferred the hysteresis loop to be controllable in 0.5 or even 0.1 increments so I could reduce that temp fluctuation.
What do you think please? Is a continuous cycle between 26-27 degrees over the course of 2-3 hours ok? It's a very gradual change both up and down, so I think so (but I may look to swap out the controller to one with finer resolution).
Power consumption is pretty much exactly the stated 72W when running, almost zero when off. The fans are pretty noisy when the chiller is running - loud fan hum similar to a noisy desk fan. I think I can probably quieten them down a fair bit by modifying the case as it seems to be the slots on the front (rather than the fans themselves) that create the noise. They look to be standard PC cooling fans so this should be an easy mod and upgrade to make - watch this space....
Here's the full gallery of my photos of the chiller
Good things about this cooler:
- Build quality (seems good enough, but a few case screws seem to have stripped threads from factory so don't tighten 100%)
- Looks (neat and tidying design)
- Small size
- Ease of use (controller manual was included)
- Works very well to chill my nano tanks
- Cooling is slow and gentle, no rapid temp shocks
- Temp reading seems accurate (after setting -1C calibration in controller)
- Long cable to temp sensor so chiller could easily be positioned away from tank
- Noise - the fans are pretty noisy!
- Temp can only be set in whole degree increments
- Hysteresis loop can only be set in whole degree increments.
- Temp calibration only in 1 degree increments (but seems accurate enough after dialing in -1C calibration)
- Probably not going to have much effect in larger tanks (I guess anything much above 25-30 litres)
My plan now is to run it for a few days at 26C to see how it goes, then lower temp to 25C if all seems well. I'll open it up shortly to see what's inside and will almost certainly be modifying the fans and case to reduce noise. I'll also see if I can get a better temp controller that will give me better (to 0.1 rather than 1 degree) control over set temp and hysteresis loop.