New Axolotl cooling system. Any thoughts?

[losfrijoles]

After over a year with a thermoelectric cooler, my wife and I finally gave up on it and bought a real cooler. We live in Texas and are currently experiencing our regular summer. Yesterday was about 101 degrees, today will be about 105. Our AC bill has been quite high trying to keep the air in our 3rd floor apartment cool enough so the thermoelectric cooler could get the tank to 20C-21C. The cooler was on 100% of the time, so the power supply was always hot (though we only had to replace it once). We've constantly struggled with fungus on our Axolotl's gills, so we're hoping that having something to get the water to a more ideally cold temperature will help solve our problems.

We originally were going to try chaining some thermoelectric coolers together to get some incremental drop in each one, but that seemed like it would cause our power bill to be even higher. They'd still be on 100% of the time and were rated for several hundred watts all together. So, we splurged and bought this instead (it was about $350 when we bought it a couple weeks ago...looks like it's a lot more expensive now).

I figured I'd share our setup, how we put it together, and see if anyone has any thoughts. Our Axolotl (Eris) lives in a 20 gallon tank which we hope to someday upgrade to 40 gallons, since she doesn't seem to have much room to swim.

We started out by going to home depot and buying some PVC to build ourselves an intake:

The sponge was from our local aquarium shop. We didn't glue any of the fittings so that it could be easily cleaned, but I did jam a bunch of teflon tape in there to stop leaks and make it harder for it to fall apart. It seems pretty sturdy. We only have 4x 1/4" holes drilled in the intake to control the water flow a bit. The pump we got does not have any sort of intake flow control and seems to be quite powerful (it says it can spray water about 4ft, and I don't doubt it). Our holes are about 2" from the bottom so that there's no way she can push the sponge up and get herself stuck to the intake. The pipe is 1" ID vinyl.

The intake goes to a 550gph pump. Every seal in the pump I had to augment with teflon tape to stop all the leaks. It is a submersible pump, but I found that it gets warm while running (it is a 40W pump) and so it seemed simpler to have it running externally. It also gives our Axolotl a little more space to move, since the pump is pretty large:


After the pump, we have the cooler. We are using 3/4" ID black pond tubing (we would have used it for the 1" section as well, but our aquarium shop didn't have any).

This cooler is amazing! It gets our tank from our regular 25C-22C (25C is our tap temperature) down to 16C in about 15 minutes. It only needs to run every hour or two for about 10 minutes to keep it that cold.

The cooler then goes to our exhaust which is just a regular spray nozzle:

This is our biggest issue so far: Our Axolotl hated this thing at first. When we first turned it on, the flow was high enough that it was violently waving her gills halfway across the tank. She went and hid in her flower pot all night. We moved a bunch of the tank stuff (a stick, some fake rocks, a tree, a bunch of false plants) over in front of the exhaust and she's much more ok with it now; floating around, sitting on the bottom, and having a great time.


We're probably going to replace the spray nozzle with a piece of PVC with a bunch of little holes in it (a custom spray bar...we haven't found a 3/4" barb-fitted spray bar and we can get the parts for it from home depot for like $5). That way we can probably increase the flow on the intake while not greatly increasing the current in the tank.

 

[Wulfiefluffie]

Hey. I am also in Texas fighting this summer heat. Im only cycling and tweaking my setup before i get axolotl. My bettas are happt with the heat but im struggling to break that 70 degree tank temp. Where did you get your chiller? Im assuming online. What about your axolotls? Did the chiller add to your electricity bill? (Not something that will stop my purchase just curious for budgeting purposes)

 

[losfrijoles]

I bought it on amazon (links in the original post) along with the pump. All together it was about $400. We paid extra for shipping, but that was refunded after it took them too long to lug it to our door (the chiller is seriously heavy, like 40lbs). However, if your tank is 10 gallons or less, then you're better off going with a thermoelectric cooler based on my experience. We bought a thermoelectric cooler about a year ago and it sorta worked, but it's always struggled with a 20 gallon tank (it's rated for 10 gallons). This new cooler doesn't even break a sweat getting it down to 16C, and it can handle a 40 gallon tank when we upgrade (we bought a 40 gallon breeder at the petco tank sale last week, but we don't have any surface in our apartment capable of holding a 350lb tank). The thermoelectric cooler we got off ebay for ~$100.

We only have one axolotl which we got from a friend who works at the local city aquarium. They didn't have space for this axolotl, so my wife took her in last year. We used ice packs for a week or two until getting the thermoelectric chiller. We've occasionally seen axolotls at our local exotic pet store, but we're really trying to keep a handle on our pet addiction (we've got two fully grown colombian red tail boas as well). They were also way too small to share a tank with our monster.

In terms of electric bill, I don't think it does much compared to appliances like the A/C, refrigerator, or oven. Our previous thermoelectric cooler ran 100% of the time (~130W) and could barely touch 20C. In terms of kWh, that's about 3.12kWh per day with the thermoelectric cooler, or about $0.37/day with a $0.12/kWh rate. Our new cooler is 460W and the pump is 40W. The cooler turns on for maybe 10 minutes every 2 hours or so in a 75F house (setpoint at 16C...I love mixing temperature units). Actually crunching the numbers, that comes out to about 0.92kWh per day for the chiller (assuming 10 minutes every 2 hours) and 0.96kWh per day for the pump, so 1.88kWh total. At $0.12/kWh that comes out to about $0.23/day so we actually may be saving money. But, we're talking pennies here. I didn't notice any difference in my "weekly summary" email from our electric company that shows me a graph of electricity usage broken down by hour.