Lighting Distance from water

[SpuD]

Hi,
just wondering the lighting distance between the lights and the surface of the water.
currently having a 3ft tank and 4 x36w PL lights but didn't use the lighting stands for the lights.
what do you guys think ?
use the stand or not use the stand.
i know by using the stand, it wouldn't be that hot and it also encourages ventiliation.
On the other hand, if i use it, will the lighting intensitiy drop?

[Simon]

spud, dun worry abt the light intensity... the gap is to ensure that there isnt warm air trapped between the water surface and the lights.. having the gap oso cools the water

[SpuD]

hi Simon,
thanks! ic, another question regarding the wattage of the cooling fan,
Just wondering the difference between the wattage used between 2x 12v DC fan 0.19Amp each with 1xAC fan with 0.12Amp. Which has a higher wattage?

2 x dc fan wattage calculation will be W=VxA
that means
0.19x2x12v=4.56W

What about the AC fan?
240vx0.12=28.8W???


[:0] [:0]

[Simon]

spud, sorry fren... me a electrical idiot that includes calculation[]

[DEA]

is it important?
i mean, seriously, what are the calculations needed for?

i just go out there and get a prebuilt AC fan, no troubles

the distance between the lighting and the tank should be near enough for the light to effectively enter the tank and not so close the light causes the tank water to overheat

some trial and error is needed
my MH lamp is ~25cm and my FL lights are 15cm away from the water, for reference

[juggler]

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On 6/1/2003 6:06:16 PM

is it important?
i mean, seriously, what are the calculations needed for?

i just go out there and get a prebuilt AC fan, no troubles
----------------

IMHO, it is important - since I am paying the bills at home.

4.56W for 30 days = 3.2kWh ==> 3.2kWh x $0.1524 (PUB rate) = 50 cents
28.8W for 30 days = 20.7 kWh ==> 20.7kWh x $0.1524 (PUB rate) = $3.10

It may not seem so much to look at the fan's electricity consumption, but add up all the life support system (filters, lightings, chillers!) for the tank and it can be quite substantial. So if a lower wattage fan (or filter) can do the job just as well, then might as well use it. The $$$ saved can help you buy your plants and fertilisers.