How to push 500+ PAR 40cm deep?

[MartinM]

It's more difficult than you might think, as I've found out.

I'm trying to hit 400+ PAR (the more, the better) on the sand bed in a 120x60x60cm (~4'x2'x2') system at a water depth of 40cm, for gigs and clams. So that's ~1500+ PAR nearer the surface. I have 2x spectra 400w halide systems that *might* do it. Maybe 4x Kessil a500s? I also have 4x GrassyCore LEDs I could mount perpendicular (~180 watts each) and could mount t5 retros on either side as well. I'm currently using ATI Stratons and I like them but they push about ~2xx PAR to the sand and ~6xx near the top, so just not strong enough (~400w total).

Really interested in the Geisemann Aurora (V8 or V12) but not sure if it'll be enough light or not.

Open to suggestions!

 

[christwendt]

It's more difficult than you might think, as I've found out.

I'm trying to hit 400+ PAR (the more, the better) on the sand bed in a 120x60x60cm (~4'x2'x2') system at a water depth of 40cm, for gigs and clams. So that's ~1500+ PAR nearer the surface. I have 2x spectra 400w halide systems that *might* do it. Maybe 4x Kessil a500s? I also have 4x GrassyCore LEDs I could mount perpendicular (~180 watts each) and could mount t5 retros on either side as well. I'm currently using ATI Stratons and I like them but they push about ~2xx PAR to the sand and ~6xx near the top, so just not strong enough (~400w total).

Really interested in the Geisemann Aurora (V8 or V12) but not sure if it'll be enough light or not.

Open to suggestions!

I’m trying to understand why you would need that much par on sand bed unless you only are keeping clams. If 400 par on sand you will fry most stuff on the rocks as it will be easily 700+ par in a tank that deep. If you are just keeping clams I would not use such a deep tank.

 

[MartinM]

Edit: Forgot to quote

 

[MartinM]

I’m trying to understand why you would need that much par on sand bed unless you only are keeping clams. If 400 par on sand you will fry most stuff on the rocks as it will be easily 700+ par in a tank that deep. If you are just keeping clams I would not use such a deep tank.

I'm only keeping clams and gigs with a few SPS, all of which are currently under ~600 PAR. I want to make sure they keep getting that amount of light even lower down in the new system I'm planning. Large maxima clams especially need a massive amount of light (mass to the cubic ratio, surface to the square ratio...). In a clam grow out facility my wife has we use solar tubes that pull in thousands of par, but not possible in our condo.

I'm not sure how much time you've spent on reefs, but anything in the intertidal zone receives thousand(s) of PAR and even more when it's out of the water part of the day. ~400 PAR is nothing for clams/gigs. Even my 200 liter zoa system gets direct sunlight a few hours a day at about 1500 PAR (granted, most of the species in that system are also intertidal). You'd also be surprised how many species are in intertidal zones and how harsh the environment is.

The depth is for aesthetic purposes (Important because it's in our condo).

 

[Reefer Matt]

Kessil a500x with the narrow reflector may be able to do it.

 

[drtechno]

Definitely Kessil a500x will do it.. You can check my build thread, but I am running 3 Radion XR30s, and 2 Kessil a500x.
My tank is 26" deep (66 cm). My lights are mounted 8" from the water surface (20 cm). The tank is 60" x 30" otherwise, with the lights mounted Radion-Kessil-Radion-Kessil-Radion.

I just bought a PAR meter a couple days ago and was shocked by how much light I had. The Radions were running at 70% and the Kessils also at 70% with the 55 degree reflector (that's not even the narrow 35 degree reflector). On the sandbed, I was hitting 570 PAR directly under the Kessils and 400 PAR otherwise (and 200 PAR at the far edges of the tank)

So my tank is deeper than what you asked about, is running the Kessils not even at full power, and without the narrow reflector (supplemented by Radions obviously) and I am already hitting the target numbers. So that will definitely work.

Edit - if you really want additional help on a single light solution - I can shut off the Radions, crank the Kessils to 100% and give you a PAR value at whatever depth you want if that is helpful. Just let me know

 

[djf91]

Why not use the 400 watt metal halides?

 

[areefer01]

I'm only keeping clams and gigs with a few SPS, all of which are currently under ~600 PAR. I want to make sure they keep getting that amount of light even lower down in the new system I'm planning. Large maxima clams especially need a massive amount of light (mass to the cubic ratio, surface to the square ratio...). In a clam grow out facility my wife has we use solar tubes that pull in thousands of par, but not possible in our condo.

I'm not sure how much time you've spent on reefs, but anything in the intertidal zone receives thousand(s) of PAR and even more when it's out of the water part of the day. ~400 PAR is nothing for clams/gigs. Even my 200 liter zoa system gets direct sunlight a few hours a day at about 1500 PAR (granted, most of the species in that system are also intertidal). You'd also be surprised how many species are in intertidal zones and how harsh the environment is.

The depth is for aesthetic purposes (Important because it's in our condo).

You can reach out to Kessil. The A500 is one option and they have another light that they are working on with a few public aquariums. The a500 with lens can punch down but it will be more focused.

With regards to light over a natural reef you are correct. However a glass box is a lot different. Be that as it may it sounds like a pendant is the proper tool for this job. Your location says Japan - you can also reach out to Kyocera Corporation. They have some kits that may work.

All the best.

 

[MartinM]

Why not use the 400 watt metal halides?

The spectra fixtures look great but their reflectors are bad (too small). So not sure if I can get the spread I want without a lot of light spill. I plan on testing though!