Height for t5 fixture and photoperiod

[michaum]

Hi I have a low boy frag tank setup for 1 month now and i am wondering if my t5 fixture is too low or too high it hangs 24 inches from water surface and if my photo period is ok here is a picture:

Here is what i have in the fixture:

60 Inches fixture
8x80 watts

6 x ATI Blue Plus
1 x ATI Actinic
1 x ATI Aquablue Special

Frag Tank:
48″ x 24″ x 10″ Low Boy tank

Photo Period:
9 hours total

9 hours --> 3 Blue Plus + 1 Actinic
6 hours --> 3 Blue Plus + 1 Aquablue Special

Thanks for all your replies and help.

 

[Crabs McJones]

Do you have or have access to a par meter? That would be the best way to tell if your lights need to be lowered to increase intensity or raised to lower it.

 

[michaum]

Do you have or have access to a par meter? That would be the best way to tell if your lights need to be lowered to increase intensity or raised to lower it.

no i don't unfortunately.

 

[Huff747]

BRS rents them now. I currently have one rented from them, think you get it for 2 weeks for a pretty reasonable price. It’s a huge help, I had Radions on my tank and my par was way too low, so I added a hybrid fixture and it’s much better now.

 

[Daniel Waters]

Hi I have a low boy frag tank setup for 1 month now and i am wondering if my t5 fixture is too low or too high it hangs 24 inches from water surface and if my photo period is ok here is a picture:

Here is what i have in the fixture:

60 Inches fixture
8x80 watts

6 x ATI Blue Plus
1 x ATI Actinic
1 x ATI Aquablue Special

Frag Tank:
48″ x 24″ x 10″ Low Boy tank

Photo Period:
9 hours total

9 hours --> 3 Blue Plus + 1 Actinic
6 hours --> 3 Blue Plus + 1 Aquablue Special

Thanks for all your replies and help.

I mount my ATI fixture around 16.5" from the top of my tank. You're obviously losing some par with such a high mounting height, but I suspect you probably get 30 to 45 par per bulb inside your tank at that mounting height (this is just my best "guesstimate" off par numbers I've taken from my fixture and BRS videos and doing some adjusting).

Now whether that amount of light is sufficient depends on what you are keeping or your goals. In general, I think corals handle T5 lighting pretty well, and I don't worry near as much about bleaching corals with T5 lighting like I might with LEDs. Most corals in my tank get 200 to 400 par as I also have some LED supplements with my ATI T5 fixture (6 bulb). I would never dream of exposing some of my corals to 300+ par under just LEDs, unless I slowly acclimated them. With T5s, it has never been much of a worry. In fact, I know some people run significantly higher par than my #'s with metal halides or T5 setups. So if you are wanting more par, I think your corals could probably handle it.

If you lowered your fixture to around 16" above tank, I'm guessing you might get 35 to 50 par per bulb throughout the tank. But, once again, this is just a guesstimate based on my experiences and measurements.

BRS video they did with par numbers is below. Mounting height is obviously different but you can see the effect on their numbers when they went from 6.5" to 8 5" mounting height. In general, you will lose some par from raising the fixture, but I find think it's as dramatic with the T5s like it can be with LEDs (and that's probably due to the T5 reflectors focusing light more down versus out in a cone like wide angle lenses might do with LEDs)

Hope that helps

 

[T-5unsystem]

With the light that high you are wasting a ton of energy lighting up the floor and the wall. You would be better off lowering and only running some of the bulbs (remove some) This way you can get the appropriate par without wasting it all over the room. Keep in mind the bulbs run in pairs so when you remove 1, another will go out. On the 6 bulb I would recommend removing the middle 2 bulbs so you have good spread (they are on the same ballast).