PAR reading wrong on 2nd hand Seneye Reef?

[Polymate3D]

Hello everyone

Early in the year I bought a Seneye reef second hand to try and get a better grip on the PAR levels in my aquarium. I am not doubting the readings. 1st up, the Fluval EVO stock light.

In this review they show the center at 4" below the water line (where the print parts on the glass) is 205 par. My Seneye reef measures 120, or around 1.75x less.

I then measured in the corners at the back and got 34. The review got between 59 and 67, making my readings around 1.85x

In the past I shrugged this off to be a poor light. The Fluval EVO is a very budget orientated package after all.

I then worked on my own 12.6W LED light fixture for a Fluval Flex, and used this PAR meter to get the desired PAR ranges. This was 100<120 at the bottom, and around 200<250 PAR half way up. I achieved this and bought multiple cheaper SPS frags and some soft coral frags, including a mushroom.

Most corals bleached within 48 hours. Ones that did survive were placed on the bottom at the 100<120 range. These then recovered, and started to grow in this 110 PAR measuring area. Everything I read says SPS montipora and 110 PAR is a bad idea, no matter growth.

I now have had a frag of Hirusuta in a place where it is supposedly getting 100 PAR and over 18 days through pictures, it is clearly growing:

Day 1:

Day 18:

Ignore the algae. Cleanup grew at work now. Would I get the growth you see in the tips of this coral under just 100 PAR, or is this meter off? Im leaning to the meter being off by about 1.7<1.8x due to the SPS growth, and the bleaching experienced under the other light where I targeted based on the measurements.

I value your opinions

- Paul

 

[brandon429]

the par meter on the seneye I would rate as totally unused here. people are using dedicated par equipment not the seneye meter simply due to reliability when calibrated against other meters, especially over time / drift etc.

what we like the seneye for are the logs of nh3 performance that shows the interrelatedness of how we all design reef tanks. (it's fascinating that a one gallon pico reef or a 1100 display reef with sixty fish have a very very very close and tight nh3 control range, impact testing scaling etc)

for ph and par, I wouldn't even consider looking at the readout.


but for nh3 logs, so savory to cycling science folks, it's the top candy. you could answer ten unknown details in today's cycling science off just that seneye alone... there's a thread on that. the seneye is handy because you can use it to refine and discover new rules on reef tank cycling science, that's the only time nh3 monitoring is needed/handy in display tank reefing. it's a naturally-controlled variable even if we don't own a seneye, but, for those who like to debate about what cycling bacteria do or do not do: that seneye is the referee final say in tests. after its calibrated, it has the final say on what cycling bacteria can tolerate in a reef tank (as compared to API ammonia reports where nobody can agree on what level we should expect, or ignore)

by the way, yours is calibrated if the nh3 is running .001-.005 nh3 at this current moment
(because, among a thousand online reviewed posted seneye logs, that's what cycled reefs run at)

 

[Polymate3D]

I may have to look at hiring a better option, but for now, the variance seems consistent. So you would fall on my opinion that the meter is out.

Thanks for your answer!

- Paul

 

[BeanAnimal]

Hello everyone

Early in the year I bought a Seneye reef second hand to try and get a better grip on the PAR levels in my aquarium. I am not doubting the readings. 1st up, the Fluval EVO stock light.

In this review they show the center at 4" below the water line (where the print parts on the glass) is 205 par. My Seneye reef measures 120, or around 1.75x less.

I then measured in the corners at the back and got 34. The review got between 59 and 67, making my readings around 1.85x

In the past I shrugged this off to be a poor light. The Fluval EVO is a very budget orientated package after all.

I then worked on my own 12.6W LED light fixture for a Fluval Flex, and used this PAR meter to get the desired PAR ranges. This was 100<120 at the bottom, and around 200<250 PAR half way up. I achieved this and bought multiple cheaper SPS frags and some soft coral frags, including a mushroom.

Most corals bleached within 48 hours. Ones that did survive were placed on the bottom at the 100<120 range. These then recovered, and started to grow in this 110 PAR measuring area. Everything I read says SPS montipora and 110 PAR is a bad idea, no matter growth.

I now have had a frag of Hirusuta in a place where it is supposedly getting 100 PAR and over 18 days through pictures, it is clearly growing:

Day 1:

Day 18:

Ignore the algae. Cleanup grew at work now. Would I get the growth you see in the tips of this coral under just 100 PAR, or is this meter off? Im leaning to the meter being off by about 1.7<1.8x due to the SPS growth, and the bleaching experienced under the other light where I targeted based on the measurements.

I value your opinions

- Paul

The problem with "PAR" readings are several fold in this context.

To start off with the seneye is going to read a different value than an Apogee or other instrument. So while 20% does not sound like a big deal.... what does "100" mean? is it 80 or 120 or somewhere in between?

Secondly "PAR" does not tell you how much of the spectrum can be used by the coral or what its overall affect on the coral is. So "100 PPFD" of mostly blue and uv is vastly different for coral growth than "100 PPFD" of mostly white.

So when you combine the uncertainty of your meter vs "theirs" - your spectrum vs "theirs" and the fact that "PAR" is not really a good metric to begin with... then "it grows good at 100" just means it does well in lower light. The actual number really is meaningless.

I hope that makes sense.

 

[BeanAnimal]

....but for nh3 logs, so savory to cycling science folks, it's the top candy. you could answer ten unknown details in today's cycling science off just that seneye alone...

....but, for those who like to debate about what cycling

by the way, yours is calibrated if the nh3 is running .001-.005 nh3 at this current moment
(because, among a thousand online reviewed posted seneye logs, that's what cycled reefs run at)

Alas - thank goodness this is a light thread and not a cycling thread.

 

[Polymate3D]

Thanks for taking the time. Sorry I didn't clarify some details about my comparison.

The review used the same Seneye Reef product and the exact same Fluval EVO aquarium light and fixture, with the data points in the same locations and heights.

I did this to try and avoid some of what you mention. PUR values I measured compared to the review are very comparable. It is just the PAR levels themselves.

I'm not attempting to get a perfect value or a target. I am simply trying to make sure I give my corals enough light to grow, and not too much to bleach.

I am aware of the spectrum side and have done extensive research recently around this. I am looking for the best approach to guide myself along. Whilst I am not happy about the measurements I have got so far, it can measure variance in a way that is going to be more consistent than the naked eye.

It does make sense and I very much appreciate you taking the time to explain further!

- Paul

 

[BeanAnimal]

Thanks for taking the time. Sorry I didn't clarify some details about my comparison.

The review used the same Seneye Reef product and the exact same Fluval EVO aquarium light and fixture, with the data points in the same locations and heights.

Ahh - well as rare as it is, that is one use case that works

I did this to try and avoid some of what you mention. PUR values I measured compared to the review are very comparable. It is just the PAR levels themselves.

There really is no way to measure PUR or a "conversion" from PAR. We don't really have a good handle on what wavelengths are needed (or what energy photo inhibition starts at those wavelengths) for most corals.

I'm not attempting to get a perfect value or a target. I am simply trying to make sure I give my corals enough light to grow, and not too much to bleach.

"100" give or take "100" is pretty low

Some corals will "bleach" on very low light with polyp/zoox bailout due to stress.. the same with very high light.

Low light typically takes longer to cause demise than burning them under intense light.

I am aware of the spectrum side and have done extensive research recently around this. I am looking for the best approach to guide myself along. Whilst I am not happy about the measurements I have got so far, it can measure variance in a way that is going to be more consistent than the naked eye.

It does make sense and I very much appreciate you taking the time to explain further!

I don't know much about the light you have, but given the readings on the lower end of the scale, I don't think for most coral you are going to run into an issue with more (even significantly more) light.

Low light - coral will often appear to be doing okay for a while, even growing but then take a turn for the worse, as they are often on the threshold of too low energy to begin with. At least that is my observation.