A Question of PAR

[Angry German]

I'm getting back into reefing. I have my 180g FOWLR doing great but I do miss having a coral reef so I am starting a 125 reef and just finished setting up the aquascape. So I have been reading about PAR and placement of corals which I never did in the past because we didn't have such fancy equipment or money back in the day. I was thinking about buying a PAR meter, but my question is, If I determine all the areas with the correct PAR readings does it really matter? Won't the corals grow into areas of different PAR especially corals that grow vertically? Do we just measure PAR for initial placement. Please educate me on this. Thank you.

 

[Dan_P]

I'm getting back into reefing. I have my 180g FOWLR doing great but I do miss having a coral reef so I am starting a 125 reef and just finished setting up the aquascape. So I have been reading about PAR and placement of corals which I never did in the past because we didn't have such fancy equipment or money back in the day. I was thinking about buying a PAR meter, but my question is, If I determine all the areas with the correct PAR readings does it really matter? Won't the corals grow into areas of different PAR especially corals that grow vertically? Do we just measure PAR for initial placement. Please educate me on this. Thank you.

I am interested in the answer. I used metal halides in the past, hung at the recommended height. Everything grew well. I can’t if the hobby is over measuring here.

 

[Nano sapiens]

To answer your question: "Do we just measure PAR for initial placement." that's mostly a yes. Many corals will grow upwards and start to receive more intensity (can be beneficial or detrimental depending on the coral type and PAR intensity level).

Different coral/false coral have ranges of PAR intensity that they can do well in. For some that range is limited, for others it is broader. Our eyes are notoriously bad at estimated PAR, hence the measurement devices.

Measuring PAR gives you a reading of the 'Photoshynthetic Active Radiation' intensity in a particular aquarium location. As an example, you might acquire a Blastomussa species coral, but unless you have a good idea of a location's intensity you might mistakenly place it in higher lighting that it isn't adapted for. Or conversely, you might acquire an Acropora species and place it in a location that has too low a PAR intensity for it to thrive.

Back in the day before PAR meters, we tended to make an educated guess based on lighting type and tank depth (to the rocks or to the sand), but I remember many times having to move a coral around a bit until it was 'happy'. PAR meters are just a tool to help us be a bit more precise and mitigate some of the guess work.

 

[xCry0x]

You can rent them from a variety of places including bulk reef supply. Often local reefing clubs have one to borrow amongst members as well.

As you said, is generally a one time thing to sanity check your lighting.

 

[Reefer Matt]

I use my par meter from time to time to adjust light intensities as the coral grow out. Coral will eventually shade each other and having the meter helps me prune the coral where it is required.

Also, as you progress in the hobby, you may change lighting and need a meter then. It mostly depends on your budget and preference, as a par meter isn't a requirement and doesn't get used daily. But you can also rent it out.