kingofnobbys
BD.org Sicko
Generally considered optimal arrangement is with a linear tube between 2/3 and 3/4 length of the tank like this :
If it's like this
Example of distances for a tank 24" T x 26" W (front to back) :
A picture says a 1000 words and shows everything succinctly and clearly.
It is likely the UV spread from the end of the T5HO will create a low UV zone (perhaps even a zone at very close to zero UV). If the UV tube is more than 12 inches from the cold end of the tank , the UV in the last 8 inches will be very low (near zero). This can be confirmed by looking at the iso-irradiance charts published here http://www.uvguide.co.uk/fluorescenttubereflectortests.htm
that look like this :
If it's like this
Example of distances for a tank 24" T x 26" W (front to back) :
A picture says a 1000 words and shows everything succinctly and clearly.
It is likely the UV spread from the end of the T5HO will create a low UV zone (perhaps even a zone at very close to zero UV). If the UV tube is more than 12 inches from the cold end of the tank , the UV in the last 8 inches will be very low (near zero). This can be confirmed by looking at the iso-irradiance charts published here http://www.uvguide.co.uk/fluorescenttubereflectortests.htm
that look like this :
