Cooler water with small tanks using fans

[diki]

I have a 1 ft cube and a 2 ft tank. Both planted and shrimp tanks. However, I do notice that the 1 ft cube tank have cooler water compared to the 2 ft tank using the same 80mm DIY fan.

I was thinking if I put 2 x 1 ft cube side by side to be cooled by 2 individual 80mm DIY fan might have cooler water or either use 2 x 80mm DIY fan or get bigger 120mm DIY fan to cool the water of the 2 ft tank? Would I get the same effect with the same volume of water? It might sound stupid but I'm trying to keep the water cool so that I can keep moss (other low light plants as well) and shrimps (CRS is the final destination). Also keeping small tanks so I can keep more tanks!

[Justikanz]

Well, if evaporation rate is the same (using the same fan in the same environment), then the tank with the smaller water volume will cool down faster. I am talking about the same evaporation rate, not evaporation amount. A stronger fan can induce a higher rate but there is only so much water that can evaporate at a time. So, for bigger tanks, use stronger fans.

[diki]

Thanks Justikanz. I do agree with what you mentioned. Will think along that line.

Just a thought. Since 2 ft tank got bigger surface area, won't it be easier to cool (but twice the volume of 1 ft cube tank)? I have not tried using bigger fans for the 2 ft tank (think it is time I use the 120mm or something that size. Got it at a discount but never use it before) but using 2 x 80mm fans currently. 1 runs 24/7 while the other runs when the lights are on. Looks like it is time to make some changes to see if there is any improvement in cooling the water of my tanks. Once I can keep the temp low enough (average around 27 or lower), will monitor the bumblebees before I try the CRS. Oh dear, my wife is going to scream at me again.

Keep the comments in please.

[dc88]

I think you have to account for the ratio of surface area over volume too. Larger surface area more evaporation, but larger volume more heat energy storage which need more evaporation to remove the heat.
So if 2 tanks with the same volume, the larger surface area one will cool down more, while 2 tanks of the same surface are the smaller volume will cool down more.
So a 2 ft tank has larger surface area than a 1 ft tank but also more volume than a 1 ft tank. Compare the surface area/volume ratio see if that tell us any relationship ?

[Ssur]

Hi,

What is the glass thickness for both the 2ft and 1ft tanks?

We cant relate both tanks to have the same temperature, unless both tanks are exactly the same, use the same type of glass, same thickness, etc.

[Justikanz]

Well, glass thickness is a much smaller factor... The majority of heat loss is through the evaporation of the tank water. In fact, most of the time, the tank water is cooler than the environment. The glass would be a conductor of heat into the water. But anyway, if I remember correctly, glass is a relatively bad conductor of heat...

[diki]

I also do not think glass thickness matters. The difference is the lights (just remember!) Using 9W desktop light for 1 ft tank while 55W magnium II light for 2 ft tank. Temp is of course hotter using the magnium light.

Anything that generates heat would affect the temp and also the effectiveness of the fans as well. I can either switch the 55W to a 36W (should be less hot, if I'm not wrong).

Also the two tanks placement is different. 1 ft tank is near a window (more air circulation) while the 2 ft tank is at the corner of the wall (less air circulation?).

Will try to get the bigger fan to work (need to source for a proper adapter for the fan) before I start work on it.