Fans size

[richietay]

currently using diameter abt 6cm fan(2 fans) cooling for my 4ft tank, temperature achieved 25.2-26.5. Water topup be abt every 3 days.

recently my brother handed me a huge fan, diameter abt 10cm, wonder will there be any different between these two fans cooling capabilities?!?!

one thing for sure, if the huge fan can achieve cooler blowing, water evaporated be more.
any comments guys!!

[tawauboy]

the bigger fan will move a bigger volume of air than the 2 smaller fan combined, if all fans are running at the same speed.
the bigger fan will reduce tank temperature faster but will not reduce tank temperature much further. this is due to heat gain from the surrounding area. however, the evaporation rate will be increased significantly.

[Jungle-mania]

It is the speed of the fan that determines the drop in temperature, but normally fan with high speed are made with larger blades. The reason is that too small a fan and too fast a speed will generate alot of turbulence. Think of blowing through a straw at the water surface.

[MosFat]

I'm just asking this out of curiosity.. what is the nominal temperature in your tanks? Mine never reaches below 29 deg celsius even when the fan is on, and the lights are off. And, the strange thing is, the temperature is maintained at 29 deg even when the lights are on. Could the external filter be contributing to the heat in the water?

[taz_boy]

how many fans do u have in ur tank???
--if only 1, and it's those 8cm type, 29 degree is logical given the recent high room temp in singapore...

normally we can acheive 27-28degree celcius using 2 fans blown across the tank...

and defitily hope ur fans are not position in the way that it's blowing the wrong direction

[Wzierbovsky]

During the day time, my tank was at 30 to 31.5 degrees everyday, and if the air conditioning is on, it goes down to 29 degrees, but never lower.

I picked up a two-fan set from NA on Sunday, and have kept it on. Normal days, tank is at 27.5 to 29 degrees; in an air conditioned room, it can rocket down to 24 to 25 degrees easily.

[sonique]

the bigger fan will move a bigger volume of air than the 2 smaller fan combined, if all fans are running at the same speed.
the bigger fan will reduce tank temperature faster but will not reduce tank temperature much further. this is due to heat gain from the surrounding area. however, the evaporation rate will be increased significantly.

so does a 2mA fan means faster speed than a 1mA? hence reducing the temp lower?

[taz_boy]

i dun really see the difference btw 2mA or 1mA fans...volt matters...iet's say if it's @ 12V and u switch ur adapter to 9V, it will decrease in speed...

the only difference i see btw fans of diff ampere is "NOISE"!!!! ...higher ampere fans seem to be noisier..

[Goondoo]

i dun really see the difference btw 2mA or 1mA fans...volt matters...iet's say if it's @ 12V and u switch ur adapter to 9V, it will decrease in speed...

the only difference i see btw fans of diff ampere is "NOISE"!!!! ...higher ampere fans seem to be noisier..

You will probably need a pair of Super Sonic Eyes to "see" the difference...

[MosFat]

I have one fan that's 9cm in diameter. The current drawn by the fan depends on the supplied voltage, that's why a power supply with a higher rated current doesn't seem to speed up the fan much.

taz: My fan is horizontal, meaning that the air flow is directed at a perpendicular to the water. Is that less effective in cooling the water than say, if the fan was blowing across the water surface?

BTW, the water evaporates very quickly, 1.5 litres a day.

[tawauboy]

i dun really see the difference btw 2mA or 1mA fans...volt matters...iet's say if it's @ 12V and u switch ur adapter to 9V, it will decrease in speed...

the only difference i see btw fans of diff ampere is "NOISE"!!!! ...higher ampere fans seem to be noisier..

when supply voltage to fan is reduced, the current used will reduce as well. higher amperage fans are definitely noisier because fan speed is higher.

[taz_boy]

I have one fan that's 9cm in diameter. The current drawn by the fan depends on the supplied voltage, that's why a power supply with a higher rated current doesn't seem to speed up the fan much.

taz: My fan is horizontal, meaning that the air flow is directed at a perpendicular to the water. Is that less effective in cooling the water than say, if the fan was blowing across the water surface?

BTW, the water evaporates very quickly, 1.5 litres a day.

1 x 9cm may not be sufficient in ur case, if u got budget , go for another 1...won't cost much..

placing it perpendicular should be fine, there used to be a thread for poll on how folks down here placed the fan, if i nv remember wrongly, it's a bt 50-50..
personally, i placed 2 fans 45 degree at on side of my tank blowing the water across from the back to front...manage to acheive 28degree in the current hot weather..

just my 2cents worth...

[taz_boy]

a...personally, i nv bother to check how much water evaporate, av i think is 5-7cm per week for my 3ft tank...

[zysfer]

If the surface water reached its maximum iteration with the air, a bigger fan will not be of much use.