This the season for *chillers*

So it’s hit mid 70s this week and being this will be my 225s first spring/summer I didn’t how the tank would react. Well it’s hitting close to 81 degrees in mid day… 81 degrees doesn’t scare me, the fact that it hit 81 degrees on a mid 70s day, however, is cause for concern! So maybe it’s time for a chiller! Wait, I do t have an extra 800 bucks lying around to go purchase one so how about a DIY project! Thinking of modifying a small fridge and using clear vinyl tubing (100’ or so of 1/2") and submersing it in a liquid that won’t freeze, using my apex as a temp controller, it would turn on a pump and allow the water to circulate thru the fridge in the cooled liquid until a desired temp was reached! I’m thinking about using a 50/50 mix of alcohol and water (kind of like washer fluid) to ensure that the color would show if I had an issue with leaks. Any thoughts on this? It seems like a legit idea, using liquid as a better heat transfer instead of air! Just want to make sure I’m not missing or over looking any details. :-)### ChillPill


People have been using mini fridges for some time to do just that. Since it is a fridge, not a freezer, and since you are circulating the water there is no need to worry about freezing. That said though, a mini fridge simply does not have the capacity to cool a tank your size. I need to know more about your system before I can do a calculation though.

I’m surprised your temp got into the 80s with the room temp in the 70s for one or two days. What kind of lighting (I’m guessing MH), what is your return pump, how many powerheads are in the tank (and what kind), what is the temperature of the room maintained as, is the tank covered, do you have a canopy, if you have a canopy is it vented with a fan?

Well the tank sits in a 4 seasons room which has glass doors as “walls”. The room is climate controlled yet it’s way to early in the season for a/c. The tank isn’t covered and I use 3 AI 26 LEDs. I have one in sump pump (Sicce 3200 gph) I do have covered on the tank but they are getting tossed (temporary cover until I returned home) I have 2 gyre 150 powerheads that are set around 30%-40% power. I also have approximately 275 gallons which in the near future will increase to close to 300 gallons. i also have a eshopps s-300 skimmer. I know I did the calculations on it before and it was showing a 1/4 horsepower chiller. I believe it’s due to the room it is in. Yet it is pretty shaded with blinds and when it blooms it has a huge oak tree for shade as well.

1/4hp sounds about right, assuming that room is kept around the 80 degree mark. The problem is that those mini fridges just don’t move enough heat. You’ll be lucky to get 100 BTU/hr out of it. Remember, they are designed to cool a fixed volume and expect the door to be closed most of the time. In essence, by pumping water through it, you are leaving the door open.

If we assume all of your tank components add 300 watts of heat to your tank, that’s 1,023 BTU/hr you need to pull out. That’s 10x what a mini fridge can do. Even if your equipment adds just 50 watts of heat, that’s 170 BTU/hr almost double what the fridge can handle.

Unfortunately, that approach simply isn’t feasible for a tank much bigger than around 25 gallons. If you compare the amount of heat the mini fridge can pull out (100 BTU/hr) to a very small room air conditioner (5,000 BTU/hr) you’d be better served adding a small air conditioner for that room and keeping it cooler.

1st, what lights are you using and how high of the water are they? How long it the cycle? You might be able to raise lights some if they are causing the rise in temp.

2nd what temp are you trying to maintain? If you maintain a lower temp it will take a bit more to raise it.

3rd your idea will kinda work, your biggest concern is gettint the water to go slow enough to drop enough heat to do what you want. Most people go te fans option 1st, put some small fans on the surface of the water and use natural evaporation.
4th there are alot of people on r2r and rc seliing chillers and for the time and money you might invest in making 1 might be better spent buying 1 that actually works.

[quote=“beadlocked450r, post:5, topic:8548”]
Most people go the fans option 1st, put some small fans on the surface of the water and use natural evaporation.[/quote]
This is a great option too. Evaporating water pulls out 8000 BTU per gallon. Your home AC is going to have to pull more moisture out of the air though and you’re going to need to make sure you have a large ATO reservoir.

I use LEDs and they are about 7"-8" off the top of the water. The fridge idea was based off of getting a fridge for free and drilling holes into the side of the fridge. I know the fridge can only support so much hence why I was going to use a liquid to submerge the line from the fish tank figuring it would have more contact than air and also using the principal that the liquid would hold a better constant temp than the air inside. I was thinking of doing a flow of 2-3 times volume of water to flow thru the “chiller”. Again this was all just an idea or experiment of sorts and I definitely appreciate the responses. I know evaporation is one of the best exports of heat yet I have to dance a fine line as I have a 10 gal ATO yet evaporation comes with a lot of draw backs such as humidity and possible mold issues… I’m trying to dance a fine, albeit fun, balance of water loss and creative way of cooling water. PBJ!

Your thought were all correct. Just didn’t run the numbers :GEEK:

Here’s a great article!

Nice! That was a well put article. abcd
Well hmm time to decide if I just need to buy a chiller… verdict_in

Any chance you could just keep that room colder? (A chiller is probably going to be the most cost efficient in the long run)

Tint the windows in the sun room to help with the solar gain(green house affect) and drop your tank temp to 75 and you should not have a problem with water temps.

Oh yeah welcome home!!! PBJ!

abcd glad to be home! Yeah I’ll be doing some “tinkering” today w/ plumbing

I would try the fans first, control them with your apex so they are only on when needed if they do the job
but you end up with a humidity issue, (unlikely if the room is climate controlled and has a air return) then you can decide between a chiller or dehumidifier.

Do you have a basement? Sumps in basements are the cheapest chillers you can have lOl, im guessing that you didnt plan on the sun room getting so warm? Any chances of moving the tank to a cooler room?