acans under 400w mh?

[walkerbrody]

This should probably be in the lps forum, but not much traffic there.

I have a 110 x-high (30" tall) with 2 400w 20k mh. I was wondering if this is too much light for acans, and if not where should I place them.

[Frick-n-Frags]

start them low
and see how it goes

20kK 400w = 10kK 250w PAR wise so you aren't exactly slamming them with 400w iwasakis, then factor in the tank depth and you don't have such a hostile setup at all

[m2434]

Originally posted by Frick-n-Frags
start them low
and see how it goes

20kK 400w = 10kK 250w PAR wise so you aren't exactly slamming them with 400w iwasakis, then factor in the tank depth and you don't have such a hostile setup at all

20K should penetrate better regardless of the PAR and I'm not sure there is such a thing as low with 400W either way...

I'm sure people will disagree, but IMHO most corals will probably be photoinhibited with that much light and actually will slowly starve. The other issue The issue is, if that doesn't happen, the zooxanthellae could like the light too much and if it grows too fast can poison the coral. There is a fine line between too much and too little light, the idea of throwing everything you can afford at corals doesn't always hold. The sun gets bright, but during the peak hours, most corals "shut down" and most light collection occurs at other times. With an on/off of a bright light, there is no transition.

A few corals such as Acropora and a few others have the ability to develop very colorful protective pigments to block more light. The pigment looks great, so many people try to boost the light and get colorful corals, but if this is the case, you are close to killing your corals. Many people don't realize this, because the corals starve slowly, sometimes over a year or more.

Some SPS corals have the best defenses against strong light, I'd stick with them. You might also get away with a very short photoperiod, like 4 hrs if you want other corals. And the third option: the MH i a point-source light, so off axis at the bottom should be the dimmest.

Just my .02

[walkerbrody]

Good informantion, anybody using this setup?