Water Temp and Fan Controller?

[mezz]

What I really need is a temperature sensor for the water that controls the three 120mm radiator fans. I'm fairly sure that it is a bad idea to just lower a temp sensor into my reservoir, I don't think any sensors are waterproof. Is there an existing solution for this? I may just settle on something that raises the fan speed if the cpu temp is anything higher than a few degrees above the typical idle temp.

I may just use a 12v to 9v or 7v cable, but I'm not sure what would happen under days of full load that I sometimes have. My fans are the slow speed, will they start at 7v?

http://www.t-balancer.com/english/produkt_1kanal.htm
I'm looking at the mCubed FanAmp. It looks like it would be great to control all three fans if I could somehow waterproof the sensor and get it into the water without creating a leak somewhere.

http://www.jab-tech.com/YATE-LOON-120mm-Case-Fan-D12SL-12-pr-3009.html
Can yate loon fans be chained when powered by the 3-pin? Will the overload the FanAmp? It says it can run a pump or a chain of fans.

I also want to control a fan I have blowing over my hard drives. I'm think I should use speedfan, which can detect SMART data, and plug the fan into one of the motherboard fan control spots. Is this a good idea?
I have a Gigabyte P35C-DS3R, if that's important.

Thanks everyone.

 

[DaCoOlNeSs]

just coat the sensor in a thin layer of hot glue, should do the trick.

I modded my yates so it plugged into 1 3 pin port, but that meant that I couldn't use the fans on anything else since I soldered the wires into one.

 

[mezz]

just coat the sensor in a thin layer of hot glue, should do the trick.

I modded my yates so it plugged into 1 3 pin port, but that meant that I couldn't use the fans on anything else since I soldered the wires into one.

That's good to know, thanks. I'm not very knowledgeable about circuitry (yet) so I may aim for a less potentially-irreversible wiring for my fans. Intuition says this may not be possible though.