MH Par Assessment

Syntax1235 · Dec 19, 2022

I’ve attached a Par map using an SQ-520 meter showing the par registered in many different parts of my tank. I’m using the ReefBrite MH/XHO fixture, 250watt RB ballast, and 20k RB twin arc bulbs. The tank is 5 feet long 24 inches wide and 25 inches tall. There are two fixtures on the tank installed 10 inches above the tank. I turned off my return pump and flow to get steady numbers.

Halides only

Does this look right?

blaxsun · Dec 19, 2022

Could be, yeah. Should be enough PAR for LPS and most SPS.

Syntax1235 · Dec 19, 2022

I wonder if a 14k bulb would produce a noticeable difference in par? 10k seemed too yellow for my eyes even with the xho’s on.

HudsonReefer2.0 · Dec 19, 2022

Try the 14k. I used to run aqualine Bushke 10k and loved the crisp white. I would think those fixtures would easily push 300+ halides only.

RedoubtReef · Dec 19, 2022

Why does it look like a photo from a newspaper circa 1982??

oreo54 · Dec 19, 2022

HudsonReefer2.0 said:
Try the 14k. I used to run aqualine Bushke 10k and loved the crisp white. I would think those fixtures would easily push 300+ halides only.

History..

Aquarium Frontiers Feature

Hurricane Aquatics · Dec 19, 2022

My tank is 36"L x 22"H x 22.6"W.

I have the 36" Reef Brite 250w DE fixture and at 10 inches from the top of the aquarium glass, I was getting around 340 PAR and 200 on the sandbed.

I would raise the fixture about 5 inches. That's what mine is at now, 15 inches instead of 10 as it was starting to bleach frags.

Your PAR is higher in some areas, the lower you get. That means the fixture is not raised high enough and the light isn't spreading evenly. Raise it about 5 inches and see how it goes.

Syntax1235 · Dec 19, 2022

RedoubtReef said:
Why does it look like a photo from a newspaper circa 1982??

Lol. It’s a black and white laser print of a photo with small labels stuck on. I can see what you mean though.

Syntax1235 · Dec 19, 2022

Hurricane Aquatics said:
My tank is 36"L x 22"H x 22.6"W.

I have the 36" Reef Brite 250w DE fixture and at 10 inches from the top of the aquarium glass, I was getting around 340 PAR and 200 on the sandbed.

I would raise the fixture about 5 inches. That's what mine is at now, 15 inches instead of 10 as it was starting to bleach frags.

Your PAR is higher in some areas, the lower you get. That means the fixture is not raised high enough and the light isn't spreading evenly. Raise it about 5 inches and see how it goes.

Thanks for the insight. Raising the fixture doesn’t seem like it would fix the par issue; however, there’s no harm trying. I’ll give it a shot.

what bulb where you using? I have the mogul fixture.

Syntax1235 · Dec 19, 2022

HudsonReefer2.0 said:
Try the 14k. I used to run aqualine Bushke 10k and loved the crisp white. I would think those fixtures would easily push 300+ halides only.

Were you using 250 watt with the RB ballasts?

Hurricane Aquatics · Dec 20, 2022

Syntax1235 said:
Thanks for the insight. Raising the fixture doesn’t seem like it would fix the par issue; however, there’s no harm trying. I’ll give it a shot.

what bulb where you using? I have the mogul fixture.

Oh, Mogul. I didn't know that or I skipped over it when reading. I have the DE version which is higher PAR.

No, you're right, it won't increase PAR, but it will even out those hot spots you're getting. Dual 250w halides will keep any Coral you can out in your tank. Raise to about 12 or 13 inches and see how it does. I honestly don't see you needing a PAR meter unless you're just curious.

Mogul fixtures have been used forever and still in use and no one has any issues.

I'm convinced that MH, T5, LED "PAR" is different. People will say that "Photons are photons, no matter the source." I'm not a believer of that philosophy as it's been proven wrong so many times.

MH, will grow and color anything. T5, will grow and color anything given enough bulbs, etc but it's different than MH. LED, well it will grow and definitely color, not not remotely as fast.

Long story short, you'll be just fine to grow and keep whatever you want.

Mortgaged Reefs · Dec 20, 2022

This is my opinion. I’m no marine biologist but this is based on my 20 yrs of reef keeping. Sometimes I have the tendency to stress the small things that my corals aren’t picky about as I thought. Lighting in my experience is one of them. The fact is most corals live in 20-30’ deep reefs and are getting 100-175 par. Unless they are Australian shallow reef sps. I ran an experiment with real low light settings for about 6 months and all my corals still grew. They seemed to thrive. In fact, when I slowly increased the lighting, many were visibly unhappy. The fact is: although some sps like high light, they will still grow under low light. Meanwhile, while most corals don’t like high light but will tolerate it the same as they will tolorate low light.

Bpb · Dec 20, 2022

I’d switch to 14,000k bulbs and raise them a touch. Two light sources over 5 feet is kind of pushing it on what can be reasonably expected, coverage wise. Before I changed direction on lighting I was set to use 3x250 watt 10,000k bulbs hung at 18” over the same size tank.

Raising your current bulbs will even if out but you’re going to reduce intensity considerably

Syntax1235 · Dec 20, 2022

Bpb said:
I’d switch to 14,000k bulbs and raise them a touch. Two light sources over 5 feet is kind of pushing it on what can be reasonably expected, coverage wise. Before I changed direction on lighting I was set to use 3x250 watt 10,000k bulbs hung at 18” over the same size tank.

Raising your current bulbs will even if out but you’re going to reduce intensity considerably

I do have another fixture. I could install the third fixture if I rotate the lights 90 degrees so they are lengthwise front to back, I r purchase two 400 watt ballasts and keep the fixture as is.

Thoughts?

Syntax1235 · Dec 20, 2022

Mortgaged Reefs said:
This is my opinion. I’m no marine biologist but this is based on my 20 yrs of reef keeping. Sometimes I have the tendency to stress the small things that my corals aren’t picky about as I thought. Lighting in my experience is one of them. The fact is most corals live in 20-30’ deep reefs and are getting 100-175 par. Unless they are Australian shallow reef sps. I ran an experiment with real low light settings for about 6 months and all my corals still grew. They seemed to thrive. In fact, when I slowly increased the lighting, many were visibly unhappy. The fact is: although some sps like high light, they will still grow under low light. Meanwhile, while most corals don’t like high light but will tolerate it the same as they will tolorate low light.

I agree; however, the focus of this tank is acros. I want to grow sticks and color them up.

KevinC · Dec 20, 2022

Syntax1235 said:
I agree; however, the focus of this tank is acros. I want to grow sticks and color them up.

I'm running a 400w radium in my 60gallon 24"x24"x24" tank. (along with 4 orphek led strip, total coverage)

Honestly having better growth and the amount of light is pleasing to the eye. 1 100% know im pushing the usual limit, but I thought 400w are better at 24" tanks no?

My tenuis and mille are growing fast, but I must put smoothies towards the bottom since Par is pretty strong.

Smite · Dec 20, 2022

I love my RB hybrid fixture. I didn't care for the RB brand mogul lamps though. I prefer Hamilton tech's 14k 250w mogul. It's where white meets blue, perfectly in my opinion. You'll get all the purples, blues, pinks showing up without a yellow look to anything, if that makes sense? It will also blend in much better with the XHOs on at the same time. I run them on the 250w reefbrite ballasts. I have yet to test par but it did very well for me on my last tank 48x24x15t. I just re hung it on my 50x36x26t tank. I'm pushing the limits of 250w for sure and it's only been a day but we will see how it goes.

On the 4' peninsula tank, the front glass would get film algae to the top, so I dont see 2 fixtures struggling on a 5' tank. The 36" has the moguls back to back center of fixture. I believe this is because the mogul side is always going to be lower par due to the base blocking the reflector. Having them back to back in the middle lets the overlap of the two lamps offset that par loss and also lets the reflector send more light out left to right of the fixture, increasing coverage. That's just the conclusion I came to looking at it but maybe something to try if you have your single pendants angled differently?

Syntax1235 · Dec 20, 2022

Smite said:
I love my RB hybrid fixture. I didn't care for the RB brand mogul lamps though. I prefer Hamilton tech's 14k 250w mogul. It's where white meets blue, perfectly in my opinion. You'll get all the purples, blues, pinks showing up without a yellow look to anything, if that makes sense? It will also blend in much better with the XHOs on at the same time. I run them on the 250w reefbrite ballasts. I have yet to test par but it did very well for me on my last tank 48x24x15t. I just re hung it on my 50x36x26t tank. I'm pushing the limits of 250w for sure and it's only been a day but we will see how it goes.

On the 4' peninsula tank, the front glass would get film algae to the top, so I dont see 2 fixtures struggling on a 5' tank. The 36" has the moguls back to back center of fixture. I believe this is because the mogul side is always going to be lower par due to the base blocking the reflector. Having them back to back in the middle lets the overlap of the two lamps offset that par loss and also lets the reflector send more light out left to right of the fixture, increasing coverage. That's just the conclusion I came to looking at it but maybe something to try if you have your single pendants angled differently?

I never considered installation position…. I have the left fixture end cap facing center and the right fixture with the end cap facing outward.

since I have a third fixture maybe I’ll rework my install and see if I can get three fiixtures over the tank. That is the most economical option.

Smite · Dec 20, 2022

Can't go wrong with another fixture and if you got it might as well try but just don't get too hung up on PAR numbers with MH. That's just an opinion of course.

So the center plate on this 36" is where the moguls are. You can see by the wall light really shoots out of the non mogul ends. Might be worth trying that first if you don't want to run 3 over the tank? Your PAR numbers look pretty even as is, which is all I'd be looking for personally to find the hanging height. With colonies and time a 3rd would probably help you more down the road.

50x36x26" time will tell but the coverage looks very even so I'll see how things respond coming from a 10x54w unit. (crap picture just cleaned the glass after hanging) If the corals start to dull or my consumption drops over an extended period of time I'll consider 400w. I haven't measured but I believe its' around 10-12" off the surface here. Once things start really growing in I do plan to move to larger pendants for the 36" front to back. My 24" had decent growth, some pieces to the edges and this fixture was all I needed.