ok i don't get it ....... (lighting question)

[jdav]

ok, this question comes from another question I posted on this board about weather 18w of PC lighting in a 2.5 gallon would be enough to keep zoas and the answer I got was basically no.....

This isn't one of those watts per gallon questions or anything, but why isn't that light enough?

This is why I think it is, and this is how my brain works so someone please chime in and tell me why I am wrong......

ok.... the little 9w coralife bulbs are only 6/58" over half the length of the tank (12").... there are two of them in the fixture. This 18w of light only has to penetrate 8" of water(less than that if something isn't on the bottom).

It seems to me, and I know I'm probably wrong, that this is more than enough light for softies and even some LPS corals since the light hits the entire tank and it seems to reach the bottom without any problems.........

Now....... With bigger tanks, you need bigger bulbs obviously to reach both across the tank and to the bottom. The bigger the bulb the more light it produces obviously so the more watts it has.


Now, When I first started reefing I was told I needed 5WPG of PC would sustain softies and most LPS corals. After researching for myself I found out that the WPG thing wasn't totaly accurate and it was more about intensity, and how the light penetrated the water.


So I guess my question is, Why isn't 18W of PC lighting over a tank that is 12/6/8 enough........... I'm so confused...


thanks in advance for any help

[jdav]

bump

[Entropy]

It might be enough for some corals. I think most people you ask are going to err on the side of caution and tell you no. The beauty of your situation though is who cares! You can buy frags in the perfect size for your tank for $5 or less. Or better yet join a reef club and they will give you this stuff for free.

So my advice is to go out and spend $20 on frags, or $20 towards a membership in the local reef club and give it a try. You have very little to lose IMO and you might just have a great time in the process.

[Colefish]

I agree with entropy. Plus 5 watts per gallon rule.. Depends on how deep the tank is.

[The Grim Reefer]

Ask in the Nano forum.

[mhurley]

[moved]

[infrared69]

i have zoas in my 2.5g aga nano and only have 13w of light. they are doing very well, in fact they are growing new heads. only complaint i have is it is a 6700K bulb and very yellow, so i will be adding some atinic supplementation in the future.

[BillnJennh]

I had the 2*9watt over a 2.5g and now have a 2*13watt over the 2.5g. With the 2*9, I saw growth, but it wasn't what I was hoping for. With the 2*13, I saw new polyps on my zoas within weeks, even though the originals are trumpeting up some for more light. I'm also keeping an open brain nicely, a froggie that has grown some, and a candy cane that is also doing nice under the 2*13. Do what you want to and you be the judge, that's the best policy.

[sellout007]

One thing you have to remeber is alot of people on these boards read something once, and then repeat it and aply it to a completely different situation.

I have a tank that is 10" high but 24" x 24". Now someone told me to use a 400w MH on that tank. Obviously thats a dumb idea. *lol*

Someone mentioned it depends on what type of tank you have. This is one of the most important questions as far as I have read. Height can play a huge factor. Obviously if you have a 36" high tank your going to need a better light to reach the bottom.

I currently have 96w of PC on my 10" high tank. I am going to to eventually try out a brain coral. Ive had many people tell me it will be fine, and then many people that tell me no way. Try it out and see what happens.


Also the watts per gallon thing to me is bogus as hell. There are just to many variables for it to be an exact science. T5 lights give off more lumens, so you can use less wattage as say PC.

[EnderG60]

watts per gallon is a stupid rule IMO, you just have to understand how each kind of light works. PC's are great for low-med light corals in tanks under 18" deep.

yes you can keep zoo's, as well as shrooms and many other corals under 18w in a 2.5.

I would recommend you get the 2x18w fixture though, because well more is better;)

[jdav]

tanks everyone!!