DIY chiller idea
 

Alrighty my bubble is nice and big so who feels like bursting it? the plan is to set up a 15g cold water tank, I'll be heading to the coast mid febuary to collect the critters to make my own livingroom tide pool, all I'm missing right now is the cold part and I'm pretty cheap so here's my idea:

tank->countertop water cooler->canister filter->return to tank

if I plumb in the water cooler I figure the line can go in the top of the jug and have the out line attached to the dispenser for the cold water, this will serve to both add a sump and chiller in one and may still be small enough to hide under/beside the stand

I do not know much about the inards of a water cooler. But we know it holds fresh water.
So the question to me is what metals if any are in contact with the water. Would not want the whole system to corrode or metal ions to go into the saltwater tank.
I know that some coolers are cooled electronically, ie, not with a system like your fridge.
Well that probablly raised more questions than it answered. Sorry

seen lots of other post for DIY chiller using bar fridges and problem is duty cycle (basically units not made to run continuously), expect simliar with water cooler

We used a bar fridge, it lasted less than a year and burned out. Worked very well while it lasted.

I think your idea will work. It's worth a shot anyways.

I've been looking at doing a cold water tank too and collecting specimens myself. The cooling part of this is the expensive/tricky part. I agree with the duty cycle comment. I've heard many stories of these DIY systems using fridges, etc and them burning out. If you design a fridge system right it shouldn't burn the thing out but you still have the risk. I've been toying around with some different ideas and seeing what works before I make the plunge.

I've used a Peltier device on a HUGE heat sink with a fan on the hot side and a ceramic post on the cold side which I'd stick into the water like a heater. With this I can hit -35C in air and about 0C in a tub of water (with some ice formation) though I don't know if it could handle a whole 15G yet. Yes, I know that the ocean isn't that cold, btw.

One thing I am trying right now is to use a heat exchanger plumbed into my taps that will cool incoming tank water. Upside, it's cheap. Downside, you're subject to the temperature of your city's water. If you're doing tide pool stuff, this should work; when diving, I typically log the shallow temperatures around 10C in the winter and up to 15C in the summer. You need about 4 - 7C for deepwater stuff.

Wow great responses, thanks everyone!

Hillegom: I hadn't considered the possibility of metals, I'll have to take
it apart as best I can and see but the electronically cooled is the peltier element Scubasteve mentioned

Mark: yes my major concern was whether or not the cooler would have the power to do the job without frying, maybe I'll get a standby just in case, the one I found was free, lots more to be had cheap (around $50)

Workn2hard2day: I hope your guys were ok when it went! I considered a mini fridge but I figured the water cooler is smaller which is a big plus and is already meant for water therefore less plumbing

Scubasteve: thanks for all the info! I considered a thermoelectric cooler, there's even a company here in Calgary that specializes in generating power for remote stations using these I sent them an email with my enquiry, I feel it may be more reliable, I may switch to it later but I'm worried about the price, in the mean time I'll keep an eye out for used 12v camp coolers and electronics recyclers, also I'm renting and on the top floor so tap water isn't really cold by the time it gets to us even if I could do the replumbing

I'll give it a try, the water cooler just happens to be free so why not? There won't be any animals for awhile yet anyways I'll keep you all posted on my progress, here's to experimentation!

My water cooler had a aluminum canister that held the fresh water, would not work out so well iguess.

Always can dig a hole in the backyard. Dig deep and ground soil temps stay around 50°F year round (examples for Lacombe and Lethbridge CDS sites).

There's a few good threads on geo-loops on RC for cooling (here's one) just need a cooling loop, titanium's nice, dump your ro/di waste into the hole to the distribute the heat, thermostats, a pump, etc. Guess too for the cost could get a chiller.

ok here is something else to burst the bubble. are you ready to wipe up water all day off the outside of the glass? unless you have a double walled insulated tank you will get condensation like crazy. also you do know it is ileagle to collect the cold water stuff like you are talking about.. dont get caught could lose your car you used to get there.

A bar fridge, water cooler ect will not have the capacity to start with to draw down the temp you will need, not to mention the metal will corode and poision your tank. so you are stuck with getting a salt water chiller, probaby a fair sized one as you are going to be looking at a 25 to 30 degree pulldown as in the summer the water temp in victoria is 56 degrees, in the winter it is 52. I just looked it up you are going to need a 1/6HP chiller or better b ut you also need to find one that is rated for bat tanks.. which means they can have a setpoint as low as 50 degrees. J&L has one that will work for $1000.00

Steve

Those water coolers with jugs require the vacuum inherent in a sealed inverted jug. As soon as you poke a hole in the jug for the hose, the water will leak out from the collar area where the jug meets the cooler.

Mitch