Adding 2nd Prime HD over Fusion 20. What do I need to know?

[TatorTaco]

I'm currently running a single Prime HD over my Fusion 20 with the long flex arm.  To resolve some shadowing (my fault on poor aquascaping) I've purchased a 2nd Prime HD along with 2 of the 90* arms.  Any suggestions on what percentage to lower my light settings to prevent bleaching?  How high would you recommend I keep the lights above the water level?  

 

Any other considerations I should keep in mind? 

 

This is a zoa dominated tank with a few gorgonians and LPS. 

 

 

 

 

[Clown79]

I don't see any shadowing, the tank is lit from panel to panel.

 

Lights should be 8-12" above the tank.

 

Too high takes light out of the tank, too low doesn't provide spread and can be too direct of light.

[TatorTaco]

Yeah, I was hoping by adding a 2nd light that I could lower the light bleed I'm currently experiencing without having to build a canopy. 

[TatorTaco]

I'll be going from a single Prime with 18" arm to double Primes with 11" arm.

 

I'm thinking I should start super low (25-30%) and then acclimate up to 50%.  

 

Sound like a plan? 

[mitten_reef]

10 minutes ago, TatorTaco said:

I'll be going from a single Prime with 18" arm to double Primes with 11" arm.

 

I'm thinking I should start super low (25-30%) and then acclimate up to 50%.  

 

Sound like a plan? 

Considering you’re putting them a lot closer to the water surface than the one currently is, then that sounds like a good plan. 

[TatorTaco]

1 hour ago, micoastreefing said:

Considering you’re putting them a lot closer to the water surface than the one currently is, then that sounds like a good plan. 

Thanks for the reaffirmation. I appreciate it. 

[Daniel91]

Holy moses that light sits high. Haha.

 

I think your plan is solid, just remember it’s easier for corals to bounce back from lower light than higher.

[TatorTaco]

32 minutes ago, Daniel91 said:

Holy moses that light sits high. Haha.

 

I think your plan is solid, just remember it’s easier for corals to bounce back from lower light than higher.

 Yeah... it’s my fault for creating 2 islands.  Light needs to be that high to cover everything. 

 

Hoping this his will fix it. 

 

Any idea how to tell when a coral coral needs more light? I know to watch for bleaching from too much light. 

[Clown79]

2 minutes ago, TatorTaco said:

 Yeah... it’s my fault for creating 2 islands.  Light needs to be that high to cover everything. 

 

Hoping this his will fix it. 

 

Any idea how to tell when a coral coral needs more light? I know to watch for bleaching from too much light. 

I have 1 Prime over my 25g. It sits at 10". My light spreads across the tank which is 24x20. 

 

I have no shadowing.

 

You are losing a lot of light at that height and effecting the par as well since most of it is wasted on walls 

[TatorTaco]

1 hour ago, Clown79 said:

I have 1 Prime over my 25g. It sits at 10". My light spreads across the tank which is 24x20. 

 

I have no shadowing.

 

You are losing a lot of light at that height and effecting the par as well since most of it is wasted on walls 

The shipment is due to arrive to me on Friday. I’ll be sure to open one of the (shorter than I currently have) mounts first and reevaluate it before I open and up and play with the extra light then. I’d much rather be out $30 for a mount than $60 for 2 mounts plus a $200 light. 

[mcarroll]

On 1/29/2019 at 7:24 AM, TatorTaco said:

Any suggestions on what percentage to lower my light settings to prevent bleaching?

Use a light meter and try to keep levels the same or just under what they are right now.   

 

Lux meters com in the form of a free app ($0) or cheap handheld($7-20), or you can use a PAR meter ($$$) if you have access to one.

 

On 1/29/2019 at 7:24 AM, TatorTaco said:

How high would you recommend I keep the lights above the water level?  

 

It would be awesome if folks would post the dimensions of the tank for questions like this.

 

Without dimensions, I can tell you that the coverage radius from 90deg lenses is equal to the mounting height. 

 

So take the smallest measurement from your tank's footprint, and divide by two.  That number should be your light's ideal mounting height, more or less, to avoid spill AND produce max coverage.

[TatorTaco]

@mcarroll, I’m sorry I didn’t see and/or respond to your comment. It was quite helpful in answering my question. The display portion of this tank measures approximately 11.5” (front to back) by 23.5” (left to right). 

 

By your math, I’d take 11.5 and divide by 2 equaling 5.75. I’ll try this out shortly and give it a go. 

 

Thanks for for your thoughtful response.