ATI T5 Light Height in a Shallow Tank

[AJ_Tsin]

Hey all just curious if anyone has any opinion or advice on how high to hang a T5 fixture from the water on a shallow reef.

I have my thoughts on it but wondering if anyone else has anything to say on the matter.

I have about 10-11 inches of water depth and an 8x24w ATI powermodule hanging over the tank. Basically anywhere I put the light there is a ton of it, but as my corals lighten up I am wondering if I have it too close to the surface at about 12" above the waterline.

Thoughts?

 

[André Silvestre]

Hi AJ,

I too have 8x24W ATI but it´s a Sunpower.

I have roughly 17 inches of water depth but my fixture sits around 4 inches above the water.

I have strong, darker colours and in some corals, colours are improving in achieving vibrant tones. If your corals are lighting up, maybe it´s not just the lights alone but rather mixed factors - light Vs nutrients. I always aim for a drier skimming and good feeding to ensure that corals get their share of food when blasting them with strong light.

In your case, I think you are more in the low nutrient side with strong light if corals keep lighting up to become pale.

Just my two cents.

 

[deeznutz1]

YOu should speak to Llyod on TFT. He's got a 12" deep tank with 4 bulb sun power. He's been experiencing light colours, he's also running bio pellets and gfo. He's had a few die lately. I told him to reduce the light significantly.
It's been a week now and he said, this corals are darkening.

What's your light schedule like?

 

[xenon]

12" above the water sound reasonable to me.

If corals are lightening, I would just decrease the photo period or feed more (not both at the same time).

 

[EuroGTI]

Aj,

Since u run zeo I figured I would add my thoughts. I was experiencing some frags getting too light and losing a little color. I figured i had too much light so I lowered my intensities a bit. My pieces that were holding color then browned out. This made me realize it wasn't light. It was nutrients being too low. We strive for ulns with zeovit, but I'm quickly learning there is a fine balance with it. I jacked my light intensities back up and started feeding a lil more. Everything is bouncing back! I think we forget how much light these sticks can take sometimes.

I think if u had too much light you would know it. I haven't seen any of your frags look bleached, but a couple are a lil on the lighter side.

 

[AJ_Tsin]

Hi AJ,

I too have 8x24W ATI but it´s a Sunpower.

I have roughly 17 inches of water depth but my fixture sits around 4 inches above the water.

I have strong, darker colours and in some corals, colours are improving in achieving vibrant tones. If your corals are lighting up, maybe it´s not just the lights alone but rather mixed factors - light Vs nutrients. I always aim for a drier skimming and good feeding to ensure that corals get their share of food when blasting them with strong light.

In your case, I think you are more in the low nutrient side with strong light if corals keep lighting up to become pale.

Just my two cents.

Hmm I think in my case 4" would be way too close... but you are right its definitely a balancing act.

YOu should speak to Llyod on TFT. He's got a 12" deep tank with 4 bulb sun power. He's been experiencing light colours, he's also running bio pellets and gfo. He's had a few die lately. I told him to reduce the light significantly.
It's been a week now and he said, this corals are darkening.

What's your light schedule like?

Thanks I will talk to him .

Light schedule is 8hr total photo period with 2 Blue + Going on for 8 hours and the other 6 bulbs for 6 hours. All the corals are healthy and constantly growing, most importantly encrusting and growing at the base so they are not starved but could be a bit on the "water is too clean side."

12" above the water sound reasonable to me.

If corals are lightening, I would just decrease the photo period or feed more (not both at the same time).

Thanks, I haven't been feeding a ton. I have a bottle of AAHC on order which will compliment the CV PIF and Xtra dosing. I think this will make a big difference. I don't feed anything else directly at the moment but I could easily up the dosage of Coral Vitalizer from 3x a week to 5x.

Aj,

Since u run zeo I figured I would add my thoughts. I was experiencing some frags getting too light and losing a little color. I figured i had too much light so I lowered my intensities a bit. My pieces that were holding color then browned out. This made me realize it wasn't light. It was nutrients being too low. We strive for ulns with zeovit, but I'm quickly learning there is a fine balance with it. I jacked my light intensities back up and started feeding a lil more. Everything is bouncing back! I think we forget how much light these sticks can take sometimes.

I think if u had too much light you would know it. I haven't seen any of your frags look bleached, but a couple are a lil on the lighter side.

Hmm interesting they are absolutely not bleaching and all are healthy so you are probably right.

I raised the light after this original post its now hanging about 14 or 16 inches from the water surface. I seem to be noticing a difference in a bit of the "macro colouring" phosphorescence and sheen or color depth that wasn't there before.

Thank you everyone for chiming in.

Plan is: Raise the light about 4-6 inches, don't modify nutrient additions or food for 2 weeks and document changes, I photograph the corals regularly so changes will be easy to spot.

If no effect. I will start by adding Amino Acid HC into the mix a few times a week and see how that effects the color over the course of 2 weeks.

I will also try and feed PE mysis soaked in Selcon a bit more to "pollute" the water, right now be-it summer and I am busy I tend to stick with only feeding Spectrum pellets which are awesome, but are also very clean...

 

[xenon]

Curious...

Do you guys shoot for detectable levels of NO3/P04 or do you keep both @ 0ppm and just feed heavier?

 

[AJ_Tsin]

Curious...

Do you guys shoot for detectable levels of NO3/P04 or do you keep both @ 0ppm and just feed heavier?

I generally just keep everything at 0 and add food accordingly. Once at ULNS I basically just tweak based on how the corals look. Test kits only come out every few weeks to make sure everything is cool as things stay very stable. I haven't tested for PO4 or Nitrate for months as they are always 0.00 or very close.

 

[SaltyWalter]

My tank is a 30 breeder, 36x18x12. My 6 bulb ATI is 4" above waterline and most of my SPS is within the top 4" of the water column and all my colors are great, however I'm not ULNS. po4 is .08-.13, no3 hangs around 5ppm, I've seen it approach 10 but not normally. I test with Hanna checkers. My light cycle is 9 hours total with blue+ on for 6 (an hour before and 2 hours after days) I find those levels safe on both ends, and the balance works very well.
I do plan to mount the light soon and it will be about 8" or so, but its because of a few of my favorite favia and chalice aren't too happy on the sand bed