Is silver reef safe?

[Deep Seven]

See title.

I'm working on making a chiller, and for the sump coil I'd like to try using a material with high thermal conductivity but it needs to be reef safe/salt water proof. I really only have 4 choices of materials that have high heat conductivity that I know of, aluminum, copper, silver, and gold.

I'm pretty sure aluminum and copper are not reef safe, so I'm considering a silver or gold plated copper coil. Silver would obviously be cheaper, but if it's just going to corrode or kill fish I'd like to know. Gold I'm pretty sure would be fine but probably expensive.

As a second option I'm considering ultra-thin pvc or silicon tubing. There is a huge difference in thermal conductivity, so it would have to be really thin to make up for it.

Whatever option I choose I want to be 100% certain the coil in my sump wont leak or poison my tank.

 

[Crepe]

Aluminum I think is reef safe I'm not sure silver is though (due to the way it's processed, not anything else). Gold definitely is. How large is the aquarium? PVC and silicone tubing is no good for this application. It has a terrible conductivity and will degrade rapidly.

Silver is going to tarnish very quickly under sea water so I wouldn't be so keen on using it.

edit: a quick google search yields that aluminum is not reef safe (uh oh) but steel is. I think you should try zinc-plated steel instead. Or stainless steel.

What are you trying to cool anyways?

 

[Deep Seven]

The final tank will be around 150g + sump and maybe refugium. Maybe a bit bigger, I haven't decided on the dimensions yet.

Atm I have a 90-100g tank that was given to me, I'm going to use that to help test my chiller, and might set it up while I dream/get the big tank built.

 

[ccCapt]

Welcome to AA!

Aluminum is fine to use. How do you plan on cooling the water? What are you going to run thru the coil? There are no efficient DIY chillers. The next best choice after a store bought chiller is using fans for evaporation. The evaporation of 1 gallon of water will remove just over 8,000 BTUs from your tank. If you have 100 gallons of water at ~8.5 pounds per gallon, that's about 850 pounds of water. That means that for every gallon of water evaporated out of your system, the tank temperature will drop by about 9.4 degrees Fahrenheit.

 

[Deep Seven]

This is going to be a temperate tank, I will need to chill the water about 30 degrees Fahrenheit below ambient temperature for a few months to mimic the winter season.

There are no efficient DIY chillers

After spending many hours searching I have to agree, that why I'm designing my own.

How do you plan on cooling the water?

A coil in a cold water bath (the cold "water" bath may be some other fliud better suited to that job), and a coil in my sump, with water circulated through the coils by a pump on a thermostat set to turn on when the water gets too warm

What are you going to run thru the coil?

A quick check of the heat capacity table and it seems water, or perhaps salt water would be best to run through the circulating coil.

 

[ccCapt]

You will never be able to drop the water temp 30 degrees without buying a BIG chiller. How would you "make" cold water and keep it cold enough to drop the water temp at all?

Bottom line is you must buy a chiller to accomplish what you want to do.

 

[Deep Seven]

My plan is to build a coldwater bath using an old de-humidfier or fridge/freezer. Most of the DIY chillers I see put a bucket in a freezer, I want to put a freezer in a bucket. Build a well insulated container, and put the cooling coils directly in the liquid with the circulating coil. My final tank will be insulated to retain the lack of heat.

Will this work? I'm not sure, but I haven't seen anyone try it, so I'm going to make an effort to make it as efficient as possible and see where it gets me.

 

[ccCapt]

It will not work. Sorry.

This may get somewhat technical, but it will explain why what you want to do won't work.
BeanAnimal's Bar and Grill - Dorm Fridge Chillers Fact and Fiction

 

[Deep Seven]

Thanks ccCapt!

That explained quite nicely why using an old fridge or freezer is not a good idea. I have to find a cooling compressor designed for a higher load and heavier duty cycle.

The one DIY chiller I found that seemed really effective was a converted de-humidifier. I'm also thinking of converting an air conditioner, I think it would have the load and duty cycle capacity I'd need. Next time I head to the city I plan on talking to a refridgeration and cooling expert to get more ideas, If I can get parts for the right price I may try building a chiller "from scrap" instead of converting something.

I'm still agonizing over what material to make the cooling coils that go in my sump. Aluminum will corrode unless I put a zinc on it, which causes the zinc to corrode instead. Would that harm the aquarium?