light spectrum?

[yeame]

ok if the reef sun light on the equater is 6700 at noon then why does every one use 10k-20k bulbs on their tanks,and with all the sand and live rock most of my corals are pretty high up in the tank like 6-10" under the lights,then most people have 175-250wpg above their corals because at least 4wpg is recomended for most corals and 7wpg for sps now this is at 16" deep so now the questions is this befor the sand,rock or after its in the tankand why do I need to have lights that are to strong and worry about bleaching my corals

( my 75g reef has 130#sand and 150-175# of live rock my lights ar 210w of 6700-10k and 170w actinic PC and vho this lighting works great on all my corals from my toadstool to the mushrooms and the green pavona caoral and even my stylaster venstua coral and this lighting didn't cost more than 200)

 

[Blown 346]

People use 10 and 20 K bulbs for the reason that the yellow color in the lower spectrum buklbs is horrible. Also the 6700 K rating of the sun and the same K of a halide is completly diffent in strength, there is no way we can simulate the sun or even come close to its lighting intensity.

Watts per gallon is a horrible way to go how much lighting you have. You can actually be indrlighting the tank going by this rule.
It is best to go by intensity to get the lighting you want.

Corals will bleach if they arent acclimated to the light or there is way too much or they are too high in the tank.
You dont need lighting to be strong enoungh to bleach your corals, but placement of them is the key.

 

[yeame]

ok then why does every one frown on putting your tank in front of a window or putting directional sky lights on the tank so it can have natural light,I can see this being a problem on an incompleet eco system but isnt that what every one strives for I have a compleet Eco system in my 75 I dont change more than 5g of water every 1 1/2-2 months and that is just because?

 

[scottfarcuz]

A lot of propagation is done in green houses using nothing but sunlight. I've seen several tanks on RC using solar tubes. Some of the drawbacks are heat issues, and the color really isn't all that pleasing. Your tank would also only be viewable during daylight hours.

If you have a complete Eco system you wouldn't have to feed.

 

[yeame]

I dont
I some times give the anenome frozen shrimp but besides some phytoplex to replace what I skim out no sump just power heads and an old wisper 5 waterfall with no carbon just some rubble thats where all the little shrimp and bugs live

 

[parothead22]

When you look at color(temperature) of the light you have to take into consideration the depth we are talking about. Water refracts light pretty quicky. At the waters surface which I believe you are mislead by the color(kelvin of the suns rays) is 6700k.
At roughly 15 feet deep, the infrared, red and orange color of the suns spectrum is lost . At 30 feet, yellow light is gone. 50 feet and the green dissapears leaving blue and purple and ultraviolet lighting left thus that is why the water always appears blue in color.
I think what you were talking about, though I could be wrong, was in terms of irradiance, which is the amount of light energy(photon flux) that strikes a given area over a period of time...called lumens. The basic unit of measurement of the lumen is lux. One lux is equivalent to 1 lumen per square meter.
The irradiance of sun light on a reef at waters surface averages over 75000 lux. At midday it goes to over 120,000lux. However, at just 15 feet deep the lux drops to 20000 lux and 1000 lux at 30 feet. When dealing with light, you have to take into account h (PAR) which is Photosynthetically Active Radiation and (PUR) photosynthetically usuable radiation which are both measures of intensity, corresponding to the light that is potentially or actually useable by the zooxanthellae for photosynthesis, respectively.
Lastly, there is (PSR) photosynthetically stored radiation, how much light is actually used up and converted to chemical energy through photosynthesis.

 

[yeame]

ok still and my point 20000 at 15 feet in a fish tank we are dealing with inches how much is to much dont the corals get sun burnt?

 

[parothead22]

It has to do with acclimation time. If you buy two bulbs that are 150watt metal halides, say one that is 6700k, the other being 20000k, the lux or lumens stays the same as far as intensity. The only thing you are changing is the color rendition. Spectrum light is all that is being changed to create a color that represents a certain depth in the ocean basically.
If you are concerned with bleaching, then it will be due to the wattage change(intensity). When you change from a 150 watt metal halide bulb for example to a 250 w or 400w, then you need to be concerned with the corals bleaching etc. You have to place the corals down low in your tank if you are dealing with intensity increase. Then you can gradually raise the corals up in your tank after a few weeks as they get acclimated to your increased light. The other thing you could do is decrease the time that the new lights are on from say 10 hours to 6. That would also work to acclimate your corals then with time you can extend the amount of time the halides remain on.

 

[yeame]

I'm just wondering about all this because I've had some frags in a 20 long with PC 65w 10k and a 65w 50-50 420-10k some how the light timer didnt go off and the light stayed on for about 36-38 hrs until I cought it now my pink branching monti is half white and orange my colonial tunicate and my superman dane are both light and dull in color now they dont look hurt just "bleached" its ben about 1 week now but I've got my fingers crost

 

[parothead22]

Montipora is a hardy coral and should bounce back ok. Tunicates are a different story as they are very hard to keep. Try adding iodine to aid in recovery if in fact that is the problem(lighting).

 

[yeame]

the corals were neon colors until light was left on

 

[parothead22]

Just don't do anything except go back to the lighting schedule you had been on! Maybe check you water parameters to be sure that there isn't another underlying factor in the corals condition!

 

[yeame]

water is fine po4 is showing up now but not bad time 4 a water change any way

 

[parothead22]

Water changes are amazing huh! It is like the magical fix anything wrong with your tank solution!!

 

[yeame]

in my 75 I change only about 5g every 2 months or so and I dont feed them any more and this is with 11 fish in an agressive reef

 

[parothead22]

WOW! I'm surprised everything has lived that long. IMO, it is best to change roughly 5% of your water weekly. This is for three reasons, the first being you are adding trace minerals etc. to your tank regularly. Secondly, you are helping to remove polluted/ depleted water from your tank frequently. Thirdy, this allows for more error on your part with regards to temp., salinity etc. By performing a smaller water change each week, you are able to get away with more, because it is small, in comparison to the amount of water in your tank.
Hopefully, I explained well enough!

 

[yeame]

the tank has ben up going on 4 years havent had to do much but top it off in about 2 years I add phytoplex about once every 2 weeks and kent trace elements once a month 150-175*lr 120-150*ls in my 75g lots of mushrooms to keep po4 down some algea's for no3 the list goes on with no sump and just an old wisper 5 hob with rubble rock in it