Metal Halide

[Colin_T]

Can’t help you with PAR but compact fluoros aren’t any good for tall tanks so in a 20inch high tank a metal halide would be a better choice for stuff like Acroporas (SPS corals) and Tridacna clams. The main reason being that SPS corals, and Tridacna clams only get their food from the symbiotic zooxanthellae they have living in their tissue. They don’t get food from any other source. Therefore if they don’t get enough light, they gradually starve. If you have the corals and clams close to the top of the tank then they will be ok under fluoros, but if you have them near the bottom of the tank, they would do better under the halides.
Corals with a large surface area (leather corals) and corals with large polyps have a bigger area to absorb light from meaning they can live in lower light. The SPS corals have a very small surface area for light absorption and more light is required for them to do well.

 

[Crazy fishes]

The more I know the less I understand; these corals are really quite exceptional. I mean the human body is a wonder but I understand a fair amount of how it works and can diagnose a number of ailments, but when it comes to corals which are meant to be 'less complex' it is so hard to stay a float with all the information on flow, lighting and nutrient requirements. I think part of the problem is that we are dealing with several genus and hundreds of species. I was astounded to find out that Sinularia densa actually has a higher capacity to deal with light (optimum intensity for photosynthesis) than some montipora and porite species.

Anyway thanks for the comments and suggests Colin

Regards

 

[Colin_T]

The human body has been studied for thousands of years and is well documented. Corals on the other hand, are still fairly new to science, although they too have been known about for many years. It has only been in the last 20-30years that people tried keeping them in captivity so we are all on a massive learning curve. (In fact we couldn't get live corals in WA until the late 1980s and then we were stuck with actinic and gro lux globes for the tanks). And with the number of corals available, hundreds of different genera/ sub genera and thousands of species, it is going to take a while before everything becomes common knowledge. Right now we are on the forefront of an exciting new era. One where we can successfully keep and reproduce corals in an aquarium. It should be a great time for corals in captivity over the next 10yrs. Unfortunately it might be the opposite in the wild. But if we are smart then perhaps we can use captive bred corals to repopulate the oceans.