T5HO + 1 Prime or 2 Prime alone.

[Proxo]

Hola reefers 😄

I'm in a little 'decision pickle' i've currently set up a new tank, 32x16x18 inch (LxWxH).

I've got an ai prime hd (original) not sure what to buy though do i go with;
1 ai prime hd & buy an ai prime 16hd or my 1 ai prime hd & buy a T5HO, something like DX16 from aquaticlife?

The tank will be running your average corals to start with, hammers, frogs, acan, zoa.
Basically wonder what route you guys would go?

another prime or t5ho 🙂
 

[SliceGolfer]

Having owned two AI Prime HDs over a 24" tank, for your tank size:

 

1 AI Prime = Poor

2 AI Primes = Good

3 AI Primes OR 2 AI Primes +AquaticLife T5 = Better

Full coverage/spectrum panel like Reef Breeders 32" or Orphek or ATI T5 fixture w/no LED = Best

 

I had shadowing on the ends of my 24" tank with 2 AI Primes. I ran them at 70% intensity to get 250 PAR 14 inches below the light source. Additionally, there will be overlap of light with 2 or more AI Primes. This means you may have 150-200 PAR on the edges and 250-300 PAR where the lights overlap.

[Proxo]

Thanks for the answer, cleared my mind a lot. 
One more question though, due to the pockets at the moment - i can only afford either another prime or the T5; which one would u go for first?
 

[SliceGolfer]

38 minutes ago, Proxo said:

Thanks for the answer, cleared my mind a lot. 
One more question though, due to the pockets at the moment - i can only afford either another prime or the T5; which one would u go for first?
 

If you intend to stay with the Primes long term, then get another Prime. You'll need two at a minimum just to get some light over the entire tank. Over time you could add a third, or the AquaticLife fixture.

 

By no means am I calling @Joevember out for having a poorly light tank. I think his photo below shows the 90 degree dispersion of light from a single Prime, with shadows in the upper left and right corners. This is over a 24" long tank. Add an additional 4" on each side for your tank, and a single Prime would look like a spotlight hanging down in the center. An AquaticLife fixture with a single Prime would look blueish on the ends and whiter in the center. Two Primes are needed just to get coverage across a 32" length. With two Primes you can do like @Joevember did, place the most light demanding corals under the brightest light, place the less demanding corals on the edges.

 

[Proxo]

Beautiful, thanks for the help and information 🙂

[Joevember]

Glad my tank is useful to other people on here! 😁

I'm running a single radion, and yes, the hotspot is a problem on these single LED array fixtures. I just redesigned my whole tank to get more corals under the light. 

If you're going for a longer tank like the one you have, two would be ideal.

[Proxo]

Hehe, noticed it mine too mate - was gonna work around it but seen as i regret getting a reef tank but spent so much i can't back out, i'm going all in.
The ai prime 'metal' bracket is no good for me though, by the time i pull the top part back so light is in middle of tank it's half way through a brick wall.

I've looked up some mounting options but......... the prices, no....... i used to be a steel engineer so hopefully i can get an old mate to weld me one up for free, seen as he owes me 
a box of stella :D, also seen people put a shelf above the tank and use the shelf support as a holder, might not be a bad idea but will still prob have to make my own shelf bracket for it to reach enough....

@Joevember What is that yellow coral? i don't want, i need. 😄

[Joevember]

24k gold leptoseris, by far the brightest coral I've ever had. It really lights up under blues. Kind of pricy unless you have someone nice fragging them for you.

Here's a close up on mine:

[Ratvan]

@Proxoyou're looking at £20 for a 1inch frag plug of the lepto

[mcarroll]

On 5/1/2020 at 11:15 AM, Proxo said:

i can only afford either another prime or the T5; which one would u go for first?

I wouldn't suggest T5's at all, BTW.  No need in 2020.

 

Two spotlights with 90º lenses ought to be fine for this tank.  (90º lenses make your coverage radius equal to your mounting height...so 6" off the water you get a 12" diameter of cone-shaped light on the water. 

 

A pair of something like Kessils that had even wider lenses (120º+) would be even more ideal. 

 

But three AI's would be overkill IMO.  

 

If you think you need more coverage than two provide, then a different type of light (eg. Current USA strips, etc.) would make a better choice.  (Worth pointing out that your corals wouldn't need more coverage...that would be all-you.)

 

Here's an example diagram I made a while back for Kessils on a 4' x 2' tank, where the wider lenses allow an even lower light placement.  You get the idea of how important the reflective lighting is with this diagram....and see one reason why PAR measurements don't seem to tell the whole story on light (they don't account for any side-lighting):