Par and overlapping lights

[Letterkenny]

I’m trying to increase my par in my tank while also considering my custom lid. It just came in today and my lid isn’t quite what I ordered in terms of spacing for my lights (did a change that didn’t flow through so likely won’t fight it). I was originally hoping to add a 3rd XR15 blue in the middle of these lights to increase par for the top rocks I have my SPS on. With the new lid and how it was cut, putting a third one in the middle will have them be a bit closer than planned. That said, will I be better off adding a third XR15 in the middle or selling the ones I have and replacing with XR30s? Will that overlap with a third XR15 boost the par over the top of the two islands with my SPS?

 

[AfaceInTheCrowd]

Can you not just move each xr15 directly over the islands, depending on what you wish to keep an should be more than enough for a 24”square in a tank that deep imo

What’s the hood look like?

 

[Letterkenny]

Can you not just move each xr15 directly over the islands, depending on what you wish to keep an should be more than enough for a 24”square in a tank that deep imo

What’s the hood look like?

I’ve had them over top and am only getting in the mid 200’s par with them over top whereas I’d like to be hitting closer to 350.

I guess my main question though is don’t you get a higher par from two lights overlapping versus a bigger light?

 

[AfaceInTheCrowd]

There will be a hot spot where they overlap essentially equaling it out over the tank if you space them correctly...I’m surprised they only hit 200...maybe 2 xr30 then or 4 of what you have (be the same anyway)...

 

[Porpoise Hork]

If you have not checked it out, BRS tests these lights for the best overall PAR distribution on a tank the same dimensions as yours.

Worth a watch.

 

[Letterkenny]

If you have not checked it out, BRS tests these lights for the best overall PAR distribution on a tank the same dimensions as yours.

Worth a watch.

I’ve checked it out but they didn’t do a 3x with the lights. I did a par mapping as attached. Trying to decide if I can put a third in the middle to save some money or I’d have to sell these to get 2x XR30.

 

[Porpoise Hork]

BRS has multiple videos out for the ideal light mounting height and spacing. The recommendations made could be applied to your setup if you change the mounting setup and go with a hanging rail instead of a tank mounted system. With a hanging system you would have a lot more flexibility to space them out or add another light to the array if needed. With some creative ingenuity you could mount the rail off a shelf set above the tank, or fabricate mounting arms for it. Also with raising the lights up along with adding an additional light would get you the PAR you need at the top of the rock while not blasting your LPS out of the tank in the process.