2x 150W DE halides — low PAR?

[i_declare_bankruptcy]

Just installed 2x Hamilton Cayman Sun 150DE w/ 14k bulb and magnetic HQI ballast fixtures above my 48”x20”x21”h tank. Took some PAR readings and I’m seeing ~150s top of tank (200 right under center of fixture). Out of water directly under fixture is 500-609 PAR. That is with the fixture mounted like 5” off the water. Something seems off right?

do the bulbs have a burn in period that affects PAR? I know color changes but unsure about PAR.

First time with halides so maybe I’m doing something wrong?

 

[i_declare_bankruptcy]

Morning bump... trying to figure out if it's burn in, bad bulbs, or need to go 250w?

 

[PaulErik]

Is that 500-609 par at the water surface directly under the fixture at 5”?

Which brand of 14k bulbs?

Halides do need about 100 hours to stabilize in light output.

My Hamilton Cayman Sun with a Phoenix 150w 14k is producing right around 300 par at 9 1/2”. This is right at the water line on mine currently.

These reflectors provide very wide spread light. I had to use a 250 watt over my high light demanding corals.

 

[i_declare_bankruptcy]

Is that 500-609 par at the water surface directly under the fixture at 5”?

Which brand of 14k bulbs?

Halides do need about 100 hours to stabilize in light output.

My Hamilton Cayman Sun with a Phoenix 150w 14k is producing right around 300 par at 9 1/2”. This is right at the water line on mine currently.

These reflectors provide very wide spread light. I had to use a 250 watt over my high light demanding corals.

that’s the perfect data point thanks! Based on your data I think either something is wrong or the bulbs are still burning in — they are very new have only been running like 4-5hours total. They are the Hamilton brand 14k bulbs.
I am seeing 500-600 out of the water about 3” below the center of the fixture. 4-6” below the surface is roughly (so 9-11” from reflector) 180 PAR, maybe 220 at the center (with the fixture about 5-6” above the water). I didn’t take very accurate measurements but no matter where I put the meter in the tank I wasn’t hitting 300 PAR.

if you can hit 300@9” you’re probably producing more PAR in general than I am.

 

[i_declare_bankruptcy]

I’m sort of miffed about this as I went 150 because the power of MH fixtures is apparently way overstated. I was hoping to hit 200-250 in the top half or top third of my tank. I think I can still do this easily by adding a couple T5s to the rack.

 

[PaulErik]

Something does seem off. I personally don’t have experience with Hamilton HQI/DE bulbs though.

150W halides can pack a decent punch with a narrow light spread reflector. I have a couple double ended Giesemann halide fixtures. With the same bulb I can easily get over double the par output but the light is very concentrated right under the fixture.

The Hamilton provides very wide light spread. For my application it works well, a single reflector lighting a 24” X 24” area.


Adding supplemental lights (led bars, t5) will help boost the total par output or the reflector can be upgraded to 250W. I upgraded one so I have one of each on a tank. Allows a lower light side and a higher light side.

 

[MrPike]

Usually when people speak of halides it’s the 250 or 400 they are talking about. 150’s are kinda niche

 

[JoshH]

@jda any insight here?

 

[i_declare_bankruptcy]

I caved and added 2 T5's w/ blue plus. Raised the fixture a 2-3" from its previous position so the tubes are far enough away from the water. PAR is now 200-250 towards the top third of the tank. Still seems low but I really love the color I'm getting from this setup and my LPS on the bottom are very stoked about it. My guess is these Hamilton bulbs suck and I should try the Pheonix bulbs next if I'm not satisfied after the burn in period. I also think I'm going to add more dry rock to my aquascape to get some higher ground for future Acropora and to protect my LPS if I end up getting better bulbs (or fixing whatever the issue is if it is one).

 

[jda]

Which ballasts do you have? ANSI M81 drives these to spec and most others ballasts under drive them. You will get more output with a m81 ballast.

Keep in mind that PAR is just a measurement on a device aimed at visible spectrum... and they meters are hobby grade. PAR measurements are not everything. It is not nothing either, but be tempered about what you get out of the tool.

 

[HeyJay]

Which ballasts do you have? ANSI M81 drives these to spec and most others ballasts under drive them. You will get more output with a m81 ballast.

The Hamilton ballasts with those fixtures are M81

 

[i_declare_bankruptcy]

Yep I was sure to get the old school ballasts first that reason — they’re hot, hum, and take up a bunch of space!