How much light is to much..

[rs1831]

I'm considering using 2 250watt halides over my 40 gallon breeder. Its primarily a sps tank. I currently have a 250 over 29 gallon tank and everything is going very well. Thanks

 

[culp]

two 250 watt metal halide is just fine as long as you keep the water temp in check. to much lighting is like you saying two 1,000 watt metal halide or maybe two 400 watt metal halide.

 

[rs1831]

Originally Posted by Culp
http:///forum/post/2983541
two 250 watt metal halide is just fine as long as you keep the water temp in check. to much lighting is like you saying two 1,000 watt metal halide or maybe two 400 watt metal halide.
Thanks

 

[stanlalee]

yeah I'm not sure how much is too much but thats not too much. thats pretty much ideal if you can manage the heat.

 

[fishstick4sale]

i think 2 over a 40 is way to much in my opinion but eh iono rule of thumb so they say is 5watts per gallon max.

 

[stanlalee]

Originally Posted by fishstick4sale
http:///forum/post/2984958
i think 2 over a 40 is way to much in my opinion but eh iono rule of thumb so they say is 5watts per gallon max.
do you realize using a 5w/gallon max rule would limit everyone with a 55g and smaller to either 70w bulbs or a single 250w to cover the whole tank (or some odd combination like 150w on one side and a 70w on the other to stay below 5w/gallon

my two 150w halides over my 30g for example would be double the limit.
I dont know what the rules of thumbs are for flourescents but the relavent "general" rules of thumb for halides are:
A)
0-17" high use 150/175w
18-24" 250w
24+" 400w
for adequate full penetration
B)
one halide for every two square feet for full lateral coverage (or one per up to 3ft sq with the use of advance reflectors at the expense of raising them and sacraficing some intensity. no aquarium reflectors are designed to cover more than a 3ft sq area).
they are "general" rules because they are meant to be broken at the users discretion and competency to make do with more or less.
it doesn't matter if its a 40g or a 400g if its at that height range between 16-20" like a breeder your close enough to that transitional zone where 150-250w are acceptable, the only thing to determine afterwards is how many you need for full coverage based on length and front to back dimensions.

 

[rs1831]

Yeah, I was thinking that it would be the right amount of light. I have a 250w over my 29gallon and its doing great. I just got everything in the mail today so I'll be setting everything up this weekend. I'm pretty excited.