lighting ?

[mretree]

Hi all

I'm somewhat confused with how much light I would need to keep corals alive. The general rule when using VHO and Halide is between 3-5 watts per gal. I own a 65 watt PC. I read that PC light are stronger than regular VHO lights. For example I read that a 55 watt PC is equal to a 110 watt VHO. Is the a different set of rules for PC lights? Would my 65 watt be rated a 130 watt?

Thanks

 

[phases99]

I would apply the same rule for both PC's and VHO's. 3-5 watts for softies and some LPS. You need to consider the depth of the tank and what type of animals you want to keep before making your decision. VHO and PC's are really only good to a depth of 18". Metal Halide may be needed for for deeper tanks.

 

[darb2]

Welcome.
What equip/ setup do you have?
Vho s are supposed to run cooler than pc's. And mh can get darn hot. Keep that in mind, cause you may need to get a chiller to keep the temp down.
Look thru the lfs and books at what corals you want to keep, and find out their light requirements. Then get the lights. If you are ok with shrooms, pc is fine. But if you "gotta have" a clam, then go for the mh.

 

[mretree]

Thanks for your input.
Right now I'm running a simply canister filter. The canister has four compartments I have sponge in 2 and biol. and carbon in the other 2. The tank is 30g- 30L x 18H. I have had problems with the temp. LFS suggested to hang the light on a canopy and not the cover the tank ( no glass lid). I'll see if this brings down the temp. if not chiller it will be. Any other suggestions are welcome. I'm new to saltwater a convert from freshwater and open to new ideas.

Thanks

 

[fishfreek]

I wouldnt classify a 55W PC to be equivlent to a 110W VHO. If you put a 55W PC over a 4' long tank you will get less light over the entire tank than you would with a 110W VHO. Now if you sample the light over the 2' area of a 55W PC bulb and compair that with the same light output over the same 2' area of a 110W VHO then ya I can see how the PC would be brighter over the same space.

Would 2 55W PC bulbs be brighter than a single 110W VHO. Probably.

The watts per gal rule of thumb does NOT work with MH lighting.

I second the recommendation to remove the glass lid. Most of us dont run lids on our salt tanks so we can maximize the air/gas exchange. This will lower your temps a few degrees by it self.

What corals do you want to keep? A pair of 55W PC's would be fine for most softies. 110W VHO bulbs are 4' long so they would not work for your setup but a shorter VHO bulb would. If you did VHO I would suggest maybe 3 or 4.