New Lux Meter to check lighting for a mixed reef aquarium

[sdavi66572]

Just purchased a $15. lux meter to check my lighting for 240 gallon mixed reef, 72" x 24" and 30" deep. My lighting is 2 - 300 watt Mars Aqua led about 12 inches about water line. Here are my readings at 18 spots on my aquarium.
150 - 201 - 141 - 155 - 184 - 174
left back corner right back

653 - 723 - 502 - 581 - 720 - 610
middle row

183 - 239 - 191 - 140 - 167 - 174
Left front row

Quite a bit of drop off on front and back row. Do I need more lights or just adjustments to what I have??

 

[twilliard]

@saltyfilmfolks
@mcarroll

 

[saltyfilmfolks]

Just purchased a $15. lux meter to check my lighting for 240 gallon mixed reef, 72" x 24" and 30" deep. My lighting is 2 - 300 watt Mars Aqua led about 12 inches about water line. Here are my readings at 18 spots on my aquarium.
150 - 201 - 141 - 155 - 184 - 174
left back corner right back

653 - 723 - 502 - 581 - 720 - 610
middle row

183 - 239 - 191 - 140 - 167 - 174
Left front row

Quite a bit of drop off on front and back row. Do I need more lights or just adjustments to what I have??

Witch meter did you get?
The function your looking for should be a 10x. So for example, the middle row number, 581, is that 58,100?

The first quick note would be, your spread may be a bit low..also at the edges, take an average too, the ball strait up, AND at a slight light angle toward the light.
I know folks w par meters don't do this generally but imo they prob should, as the coral is looking at the light at this angle too esp as you at deeper in the tank.
We'd call this a half ball(to the subject) and full ball(to the light) measurement.

 

[sdavi66572]

Witch meter did you get?
The function your looking for should be a 10x. So for example, the middle row number, 581, is that 58,100?

The first quick note would be, your spread may be a bit low..also at the edges, take an average too, the ball strait up, AND at a slight light angle toward the light.
I know folks w par meters don't do this generally but imo they prob should, as the coral is looking at the light at this angle too esp as you at deeper in the tank.
We'd call this a half ball(to the subject) and full ball(to the light) measurement.

This is the Dr. Meter Lux Meter LX1010BS. When I was checking these measurements I was moving and tilting that ball around and took the highest reading.

 

[saltyfilmfolks]

This is the Dr. Meter Lux Meter LX1010BS. When I was checking these measurements I was moving and tilting that ball around and took the highest reading.

excellent.

k does the meter read x10 or x100?

538 lux is like a candle. 5380 is like a walmart and 58,000 lux is like a Mars black box at 60% or so.

Thats the meter Mcarrol uses, he might be able to help with the how to on it.

 

[sdavi66572]

excellent.

k does the meter read x10 or x100?

538 lux is like a candle. 5380 is like a walmart and 58,000 lux is like a Mars black box at 60% or so.

Thats the meter Mcarrol uses, he might be able to help with the how to on it.

It read both 10 and 100. So it is the 58000 like you said. My lights are set at about 75%. My day light lights are on from 12:00 noon till 7:00 pm and my night light are on from 9:00 am till 10:00 pm.

 

[saltyfilmfolks]

It read both 10 and 100. So it is the 58000 like you said. My lights are set at about 75%. My day light lights are on from 12:00 noon till 7:00 pm and my night light are on from 9:00 am till 10:00 pm.

ok, that makes sense then. for a 30 in tank thats prob not bad. It is high light. So its very important to acclimate all animals and keep an eye on keeping nutrints up to avoid bleaching.
If I were to recommend a Lux number for a 30in deep it would have been 40,000 and then see if you can go to 50,000.

you can experiment if you chose on different mounting height to get better spread over the tank.
Its a little bit complicated but if you are at good DIY, you can take out the lenses(or some of them) and lower the light as well.

 

[sdavi66572]

ok, that makes sense then. for a 30 in tank thats prob not bad. It is high light. So its very important to acclimate all animals and keep an eye on keeping nutrints up to avoid bleaching.
If I were to recommend a Lux number for a 30in deep it would have been 40,000 and then see if you can go to 50,000.

you can experiment if you chose on different mounting height to get better spread over the tank.
Its a little bit complicated but if you are at good DIY, you can take out the lenses(or some of them) and lower the light as well.

I just turned my lights down from the highest number of 723 in middle to 440 or 44000. I turn both my day lights and night lights down to zero. Used my meter to get day lights up to 35000 and then turn my night lights up to get the 44000. A big change. Is this to much??

 

[saltyfilmfolks]

I just turned my lights down from the highest number of 723 in middle to 440 or 44000. I turn both my day lights and night lights down to zero. Used my meter to get day lights up to 35000 and then turn my night lights up to get the 44000. A big change. Is this to much??

Down in intensity is not generally a problem.
I make an even ramp up, then down. leaving the longest intensity in the middle.
The ratio or color mix you like is up to you.
My highest intensity is all the colors combined.

does that make sense?

 

[sdavi66572]

Down in intensity is not generally a problem.
I make an even ramp up, then down. leaving the longest intensity in the middle.
The ratio or color mix you like is up to you.
My highest intensity is all the colors combined.

does that make sense?

Yes it does make sense, but dropping dowm from 72000 lux to 44000 lux that is almost 40%.Do you think I have been cooking all my sps corals. My lps corals for the most part do pretty well. Just started getting sps having a pretty hard time with them.

 

[saltyfilmfolks]

Yes it does make sense, but dropping dowm from 72000 lux to 44000 lux that is almost 40%.Do you think I have been cooking all my sps corals. My lps corals for the most part do pretty well. Just started getting sps having a pretty hard time with them.

if the corals are are they they are ok. That's the honest truth. If you maintain the nutrints and alk and flow correctly and the corals are fine, then they are fine.
And yes acros are a different animal. very sensitive and take time. zoas are easy in comparison as the move retract etc.

 

[sdavi66572]

if the corals are are they they are ok. That's the honest truth. If you maintain the nutrints and alk and flow correctly and the corals are fine, then they are fine.
And yes acros are a different animal. very sensitive and take time. zoas are easy in comparison as the move retract etc.

I try to keep my tank pretty stable 240 gallon. Been having a little issue with phosphates ( been moving a lot of live rock) been dosing red sea no pox to keep phosphates about .02. Nitrates 10, alkalinity 9.8, mag. 1400, salinity .026 and calcium 450. I dose BRS two part for alkalinity and calcium. I have been up and running since 7/2014.

 

[saltyfilmfolks]

I try to keep my tank pretty stable 240 gallon. Been having a little issue with phosphates ( been moving a lot of live rock) been dosing red sea no pox to keep phosphates about .02. Nitrates 10, alkalinity 9.8, mag. 1400, salinity .026 and calcium 450. I dose BRS two part for alkalinity and calcium. I have been up and running since 7/2014.

Im jealous. Sound like your on the right track.

 

[mcarroll]

Yes it does make sense, but dropping dowm from 72000 lux to 44000 lux that is almost 40%.Do you think I have been cooking all my sps corals. My lps corals for the most part do pretty well. Just started getting sps having a pretty hard time with them.

Down can be a huge problem as well....it's how I toasted my tank full o'Monti's when I switched to LED.

I wasn't using a light meter back then (supposedly you needed a PAR meter...ha) so I was trying to do like everyone and base my lighting off of what I read.

So I thought my new LED's were "really intense". I also thought my old halides were "really intense".

In reality, I dropped the peak lux down from 50,000+ down to around 14,000 lux. Didn't learn that until I retroactively measured my old and new lights. WITH A LUX METER.

I'm not sure what Radiums clock when brand new, I only have expired bulbs to test....the differential could have been more significant.

At any rate, after it was all said and done, I harvested almost 15 gallons of dead Monti. skeleton out of my 50 Gallon tank. (Ultimately only lost the Green and Purple monti's....the rest recovered from lower growth. Yes, I saved all the skeleton. LOL)

Very little food was being aded to the system as I have always have no fish – or almost no fish, like my three little Barnacle Blennies now.

A well fed system might have had a different or less severe outcome.

Just the same, I would keep lighting changes small in all cases. <2500 lux per change, and no more than a change a month would be nice and conservative.

2¢

 

[mcarroll]

@sdavi66572 BTW, do your lights come with 90º or 60º lenses?

With 90º lenses you should be able to get away with that 12" mounting height you have....maybe just a little higher, but light spill may get significant quickly. I suspect you have 90º lenses, but you should confirm if you don't know for sure.

If you have 60º lenses, then you would have room to go up to 20" off the tank.

With 120º lenses, 6 or 7" would be more favorable, but I would wonder how much light you'd be getting to the bottom of the tank.

The lux meter in a ziplock bag would answer that!

Even with 90º lenses, I'd be a little curious just what the bottom is getting.

Just to use a well-known, published comparison: The Orbit Marine Pro puts a comparable amount of light at the water surface as your current setup, but even with 60º lenses only gets around 2500 lux to the bottom at 30".

So it's worth measuring at least once.

It's also worth noting that those fixtures are cheap enough that you could opt for a closer mounting height AND to run two sets of them, one in front, one in back. You would be able to run them all at about 1/2 power, but coverage would be around 100% with very little fall-off from front to back.

Last point: Unless your rocks reach all the way to the top of the water, your corals aren't going to be subjected to all that much intensity. Yes, the surface is brightly lit. But the bottom is probably mesophotic – borderline for photosynthesis. That doesn't mean corals won't grow there, but it means that they could be pretty dependent on dissolved nutrients as well as particlate nutrient sources even for carbon.

 

[Syntax1235]

May I chime in here?

Is the probe of this lux meter waterproof? If not, how do you submerse it?

 

[saltyfilmfolks]

May I chime in here?

Is the probe of this lux meter waterproof? If not, how do you submerse it?

you can purchase a meter with a submersible probe, or diy a ziplock etc. Mac And I have both found however that by measuring the surface intensity you can pretty well guage the penetration to the bottom.

 

[Syntax1235]

you can purchase a meter with a submersible probe, or diy a ziplock etc. Mac And I have both found however that by measuring the surface intensity you can pretty well guage the penetration to the bottom.

Ok. So could you point me to a post or thread that explains how to make the intensity estimations for different depths?

 

[saltyfilmfolks]

Ok. So could you point me to a post or thread that explains how to make the intensity estimations for different depths?

Neither of us have yet to write(or publish actually) a comprehensive guide as Lux is generally a heated topic and we suffer from some fairly extreme trolling to be honest.
But I do recommend thinking in terms of PAR.. How much Par do you want to deliver to a your tank. What light will you be using. How deep is the tank. A frag rack will need much less than a 24in deep tank.
Then, using some fairly standard Lux par conversions avail set the lux.
Here are the conversion numbers Ive found to be very close.
10 to 14k T5 and 14k MH conversions is 40
Blue MH and t5 50
Led @1:1 ratio at 60

From what I have seen these numbers provide a very close estimate. If you do the math in between, ie 45 55, you'll get a good estimated range.

Fwiw, on both of my tanks(20 and 24in deep) I run 40,000 lux at the top. this is IMO med high Par. A kessil ap700 and 360 w standard lens both deliver 35000 lux from a distance of 12in. but many dont run it at full intensity.

 

[Syntax1235]

Could you explain the lex@1:1 ratio at 50?

I have a pacific sun led,t5.... if the lux meter reads 50,000 how does that convert to par at the surface and at the bottom of a 125g tank? I just want to make sure I'm following all of this.... thanks.