Par meter

[Hilltopreef90]

I went ahead a bought a par meter and was surprised at the readings, and I’m also glad I went ahead and got one so I can place my corals in better areas.
My ricordea’s were way down on the bottom but for some reason that side and area was getting much higher readings, and I now know why they’d been hiding inside the rocks (smart corals, lol) I moved them to a better spot.
I do have a question, should I shut down the powerheads when taking readings or leave them on ? I didn’t see that much difference with it on or off.
I was also surprised that even at my highest point I wasn’t getting very high readings.
I’m using two xr30 radions on a 48 long tank (90 gallons)
I think what surprised me the most was the areas that I thought would be higher weren’t and some areas on the bottom were much higher then expected.
Another question should I measure at different times of the day ?
I placed my acans where it was registering 35-60 par is that too low ?
ideally what par should a hammer coral be at ?
Cyphastria coral how low and what’s the highest
Same question with gsp

 

[blaxsun]

Yes, the difference between the actual PAR reading and what the eye perceives can be quite a difference.

You may find that the PAR readings vary ever so slightly with no water movement. Yes, you should definitely measure at different times of the day (or different points of your light settings) - especially peak intensity.

35-60 might be a bit low for your acans (I'd aim for a bit higher, maybe 75-125). I have my euphyllia between 50-100. I have my cyphastrea around 100. My GSP are all between 40-65.

 

[Hilltopreef90]

Thank you

 

[Hilltopreef90]

Yes, the difference between the actual PAR reading and what the eye perceives can be quite a difference.

You may find that the PAR readings vary ever so slightly with no water movement. Yes, you should definitely measure at different times of the day (or different points of your light settings) - especially peak intensity.

35-60 might be a bit low for your acans (I'd aim for a bit higher, maybe 75-125). I have my euphyllia between 50-100. I have my cyphastrea around 100. My GSP are all between 40-65.

I was getting super low readings and realized it was later than I realized and the lights were actually ramping down, I reset them and there was a significant difference.
I do atleast have a general idea now where the lower light areas are and where I can move the corals if needed.

 

[Chrisv.]

Par meters are awesome. It's interesting to see unexpectedly high par spots due to reflection of light off of the front glass.

The difference between what looks bright to the human eye vs what is high par is striking. I do think this is one area where metal halides shine (ha!). The visual light and par-producing wavelengths tend to be more closely matched, so your high par tank never looks dim. One can always crank up the non-blue channels and get more of the visible spectrum without much of a par bump.

If only MHs were more manageable in terms of heat. Alas.

Have fun with your par meter!

 

[Hilltopreef90]

Par meters are awesome. It's interesting to see unexpectedly high par spots due to reflection of light off of the front glass.

The difference between what looks bright to the human eye vs what is high par is striking. I do think this is one area where metal halides shine (ha!). The visual light and par-producing wavelengths tend to be more closely matched, so your high par tank never looks dim. One can always crank up the non-blue channels and get more of the visible spectrum without much of a par bump.

If only MHs were more manageable in terms of heat. Alas.

Have fun with your par meter!

Will I get a more accurate reading if I turn off the powerheads

 

[Chrisv.]

Will I get a more accurate reading if I turn off the powerheads

Well... It's complicated. The thing is, the surface of the water acts as a lens, and you will see that if you turn off the flow you get a more stable reading. With flow on, the shape of the lens is constantly changing due to the ripples at the surface, and you will see the meter bounce around a lot. The fluctuations are 100% real, but most people like to test with the pumps off to get a sense of what the steady state par is. So it's not so much a matter of accuracy as it is measurement stability.

 

[Hilltopreef90]

Well... It's complicated. The thing is, the surface of the water acts as a lens, and you will see that if you turn off the flow you get a more stable reading. With flow on, the shape of the lens is constantly changing due to the ripples at the surface, and you will see the meter bounce around a lot. The fluctuations are 100% real, but most people like to test with the pumps off to get a sense of what the steady state par is. So it's not so much a matter of accuracy as it is measurement stability.

So as long as you keep in mind the lower and higher measurement when placing corals you should be ok?

 

[Chrisv.]

So as long as you keep in mind the lower and higher measurement when placing corals you should be ok?

You will get strange high spikes. I'd ignore them. Stick with what seems to be the most common. There is no benefit to measuring with the pumps on, so it may be more straight forward to measure with them off... unless you just don't want to turn them all off (guilty of this).

 

[SantaMonica]

If only MHs were more manageable in terms of heat

The new MH LED's will fix this right up

 

[Chrisv.]

The new MH LED's will fix this right up

Mh LEDs?

 

[Hurricane Aquatics]

I'm late to this, but you're getting readings if PAR being higher in areas based on your mounting height. Raising the lights up will give you more coverage and even out the par.

I would mount them about 10 inches above the water surface to start.

 

[Hilltopreef90]

I watched a brs video on using the par meter and realized that I’m getting too many different par readings on the bottom of my tank and so I need to start out with adjusting my light to get more of a level reading throughout the bottom, that being said what should I shoot for as far as the lowest par on my sand bed ? 50? 75? I have acans, cyphastria and zoa’s on the bottom near or on the sand bed so what would be the lowest I’d want to have the par ?

 

[Chrisv.]

I watched a brs video on using the par meter and realized that I’m getting too many different par readings on the bottom of my tank and so I need to start out with adjusting my light to get more of a level reading throughout the bottom, that being said what should I shoot for as far as the lowest par on my sand bed ? 50? 75? I have acans, cyphastria and zoa’s on the bottom near or on the sand bed so what would be the lowest I’d want to have the par ?

50-75 is fine for most acans and cyphastrea. Opinions vary on zoanthids. Some of the nicest zoa tanks I have seen run 200-300 par. I run mine at about 125 and I think the species and strains I have are adapted to that level. You will see Zoanthus species in waist-deep water in some areas of the keys though.... Without belaboring the point, yes 50-75 is great. Keep in mind that new sand (not sure if your tank is new) has a high albedo and will reflect more par today than it will when it has a little microalgae on it from being in the tank for a few months.

 

[Hilltopreef90]

50-75 is fine for most acans and cyphastrea. Opinions vary on zoanthids. Some of the nicest zoa tanks I have seen run 200-300 par. I run mine at about 125 and I think the species and strains I have are adapted to that level. You will see Zoanthus species in waist-deep water in some areas of the keys though.... Without belaboring the point, yes 50-75 is great. Keep in mind that new sand (not sure if your tank is new) has a high albedo and will reflect more par today than it will when it has a little microalgae on it from being in the tank for a few months.

 

[Hilltopreef90]

So the par will change on the sand bed if it’s only a couple months old ?

 

[Chrisv.]

So the par will change on the sand bed if it’s only a couple months old ?

new sand is reflective and your par just above the sand bed will decrease as the sand ages, gets covered with biofilm and becomes less reflective.

 

[Hurricane Aquatics]

Shoot for around 100 or 125 on sand bed. PAR isn't going to change on the sand bed because of reflection, it isn't a mirror.

Adjust the light for 30% overall intensity and then start changing your mounting height from low to higher. Your spectrum at AB+ will be fine and you can meds with that once you get your height set correctly.

 

[Hilltopreef90]

Shoot for around 100 or 125 on sand bed. PAR isn't going to change on the sand bed because of reflection, it isn't a mirror.

Adjust the light for 30% overall intensity and then start changing your mounting height from low to higher. Your spectrum at AB+ will be fine and you can meds with that once you get your height set correctly.

I measured the car again and if I adjust the height any higher the par dips below 50 on the Sand bed I don’t know if it’s because it’s an older style tank or it’s because my Radions are generation two and three but the par is much lower than you’d expect on the sand bed if I drop the intensity lower or raise up the lights
I have acans on or close to the sand bed and worry 100-126 would be too high

 

[Hurricane Aquatics]

I measured the car again and if I adjust the height any higher the par dips below 50 on the Sand bed I don’t know if it’s because it’s an older style tank or it’s because my Radions are generation two and three but the par is much lower than you’d expect on the sand bed if I drop the intensity lower or raise up the lights
I have acans on or close to the sand bed and worry 100-126 would be too high

I don't think you understand what I'm saying. You have to first get your mounting height right. I'm not sure how you've mounted the fixture, but let's go for 9 to 10 inches from the water surface to the bottom of the light (where led pucks are). So 9 to 10 inches between the water surface and the light.

Now, read par and adjust accordingly. If it's too low, adjust 10% more intensity and read again. You should have around 200 to 250 about 4 to 8 inches under the water surface.

Then go for a middle of the tank par of about 130 to 160.

Sand bed, you should be pretty close to what you need. 100 PAR isn't going to hurt any coral.

You want a even distribution of light so you will know where to place various corals.