Frag Tank Lighting Distance

[Coronus]

Wanted to get some opinions on this. My frag tank is 48x24x12 Deep Blue.
Lighting is a 48 inch 6 bulb ati.
Trying to understand distance from water to fixture. Its been hard to dial this in.
Because the height of the tank is so low, is par higher with no water or with water?

 

[luke33]

Par is higher through air. It depends on what your wanting to grow. For sps i'd probably have the fixture 10-12" above the tank, maybe even 14-16" as 12" deep is pretty shallow. I keep my fixture 10" above my 24" tank and still pull 300 par at the bottom.

 

[saltyfilmfolks]

, is par higher with no water or with water?

Par is slightly lower on a meter with water due to refraction.

decide how much par you want on the frags, or top of the tank. As a rule of thumb(for me) I count at 200 par per tube at 12 in. (its less 165-175 etc)
so at 12in your light could be 1000 par in the center, at the top of the tank.
to dial it in further you would need a par or lux meter.
If you use a lux meter, divide the lux by 40 and 50. its probably between the two.

 

[Coronus]

I am like 8 inches above my 125 and its great. I grow all sps. My frag system is separate and the light is about

Par is slightly lower on a meter with water due to refraction.

decide how much par you want on the frags, or top of the tank. As a rule of thumb(for me) I count at 200 par per tube at 12 in. (its less 165-175 etc)
so at 12in your light could be 1000 par in the center, at the top of the tank.
to dial it in further you would need a par or lux meter.
If you use a lux meter, divide the lux by 40 and 50. its probably between the two.

Par is slightly lower on a meter with water due to refraction.

decide how much par you want on the frags, or top of the tank. As a rule of thumb(for me) I count at 200 par per tube at 12 in. (its less 165-175 etc)
so at 12in your light could be 1000 par in the center, at the top of the tank.
to dial it in further you would need a par or lux meter.
If you use a lux meter, divide the lux by 40 and 50. its probably between the two.

I like what your saying but not understanding fully. Would it be 1000 or 1200?

 

[Coronus]

So at 14 inches it would be?

 

[saltyfilmfolks]

I like what your saying but not understanding fully. Would it be 1000 or 1200?

200 per tube is fast math. Its actually less.

I count at 200 par per tube at 12 in. (its less 165-175 etc)

this will depend on age of tubes, fixture, ballast, reflector etc.

So at 14 inches it would be?

less than a 1000? lol.
prob still in the 700 800 range give or take.

what par range are you going for is a bigger question. IMO you may want to pull tubes, if your growing acros it really depends on your thoughts about par. 350 for 8 or ten or blast em old school. both work.