Need help understand my lighting needs and Par readings please.

[Volkman]

Hi all,

I have a 180g (72"'x24"x24") tank with 4 Aqua Illumination Vega-Blues that are about 10" off the water, my lighting schedule is attached.

Question is, what is considered high, medium and low light readings? I've been having trouble keeping Sps, Hard Corals etc and my levels are pretty much spot on.

Nitrite/Nitrate: 0
Phosphates: 0
Alk: 9
Calc: 430
Mag: 1200
Ph: 8.2-8.3
Temp: 78
Orp: 480-500

Everything is constant and stable. Reef Octopus DC250 internal Skimmer, 2 Vortech Mp40's on the sides of the tank in the center.
Dosing Alk, Calc, Mag via Bubble Magus doser, fuge with cheateo, etc with a small led on 24/7 and a home dump plant light running opposite the main tanks lighting schedule.

I just rented a PAR meter and took some reading and this is where my knowledge gets a little iffy. Directly under the lights it reads approx 2880nm. At the waterline it reads: 180nm along the back wall, 900nm center of the tank and 40nm along the front wall, all again at the water line. Mid tank it reads: 200nm-back wall, 250-300nm-center and 80nm-front wall. Bottom of the tank readings are: 80-back wall, 70nm-center and 100nm-front wall.

Can someone help me decode what these readings actually represent, ie; "this coral needs high light, this low", and what should go where? Make sense? I would love to have a beautiful sps/mixed tank and can keep zoas, mushrooms, hammerheads, palys, acans, carpets, nems, gronapora, etc very well, just cannot keep any thing else for some reason. Not even birdsnest or similar. Need some help figuring out why please..

Thanks in advance, r2r has been very helpful in the past. Appreciate it all!

Bob

 

[hart24601]

There is no hard list for this, but I can give you the numbers for the coral I have had. Remember that there can be huge differences in 1 category of coral, for example brain coral. Some bleach out above 100 PAR and I have had some in over 500 PAR and be fine.

My lower light corals like 50-100PAR - bubble coral, some LPS brains/button coral, some chalice, my SPS merulina likes even lower than 50 PAR. Things that like partial shade in my system.

Mid level 100-200. Lots of guys in here. Most LPS Few SPS. Flowerpot, elegance, some plate coral, most of my chalice, pretty much what I shoot for on the sand bed edges.

Mid-high 200-300. This is the zone that most my SPS like. Monties, acros, some LPS like hammers. This is my goal for the majority of my rock.

High 300-500. Clams, some acro, some LPS can handle it like hammers and frogspawn. I like my acros to be in mid 300's with some of the staghorn going up to 500.

Very high 500+. Not much love it here for me. The corals in the high category above can handle it, but with reduced photoperiod. Photosynthetic gorgonions seem to like it and high light clams. I have a frogspawn that lived in 800 PAR but didn't like it that much.

Remember if you have something in really high PAR you need lots and lots of flow around it. When they coral has too much light they release the extra as heat and need extra flow to avoid tissue damage. It also appears that high pH help prevent bleaching.

 

[Volkman]

Awesome info Hart, thank you! I know there is not a exact list saying this needs x, but am trying to find out what "high light" actually is, so this should help immensely. Kinda also thinking these AI Vegas have a very narrow light pattern. Any experience or knowledge on them? Would raising or lowering them affect that at all? Thanks!!

 

[hart24601]

Happy it helps! I don't have experience with those lights, but in general raising the light up will give larger distribution and less spot intensity. Hopefully someone with these lights can give more info.