new setup lighting anemone and clam

[dab1]

Hello,

My interest in my new setup is twofold. First, I would like to obtain an anemone for a couple of percula clowns I already have in an existing tank. I am also interested in keeping clams. Other corals/fish/whatever will be added such as are compatible with these.

My question is the lighting. I have a 90 gallon tank measuring 48" long x 24" deep, so I plan on obtaining a 48" long fixture of metal halide lights (and possibly florescent). As metal halide is rather unforgiving of changing and mixing and matching, it seems useful to me to get this right the first time... I had been leaning towards something like 2 250 W 10000K metal halides with some kind of actinic florescent bulbs to round out the spectrum. Specific questions:

1) Is 250 W too much intensity for 24" deep? Would 175 be better? Or can some people convincingly argue either... I seem to find both opinions out there (that for 24" you NEED 250, and that for that depth and species mix 250 W is too much).

2) There seem to be 14000K bulbs out there that some people advocate using without florescent. What would be the advantages and disadvantages of such over the florescent / 10000K combination?

 

[Len]

For a 24" tank, 250W is just about right. You can go with 400W too (my 24" deep tank had dual 400 watters for about 6-7 years). 175W isn't adequete lighting for a 24" deep tank unless you don't plan on keeping any "high light" inverts.

As for the 14KK, I'd need to see the spectral output to really comment. Kelvin ratins are arbitrary, and the 14KK might just be the same bulb as the 10KK. I've used 10KK with actinic supplementations for the past 5+ years and have been very happy with it. I like having actinics for numerous reasons, such as being able to have them come on/off on different times then the MH, the actinics adding PAR to the tank (no, they aren't just for show), and the fluorescing effect on corals that only true actinics can produce. It does cost more to to operate in terms of electricity and bulb replacement, so consider that the tradeoff.

 

[Tackett]

Dude, what I would do is this: I would stick to about 5 W per gallon of aquarium water. Always go overboard with your lighting. You can have too much and actually hurt things but it has to be way overkill. In the case that you mentioned it would be about perfect. 90 X 5=450. I would keep the metal halides as close as possible to the surface, find that happy medium where enough light is penetrating the water, but not cranking your water temperature. (halides are way hot.) So for that reason you can go over your wattage and set your lights higher to minimize heat exchange. (hope im just not babbling to you.) To make a short answer, the specs you listed seem fine with the 2 250W and like I said, find a nice happy heat:light ratio. to answer your second question, I would run the 2 10000K lights with blue actnic flourescent bulbs. Reason being this: Blue spectrum dies much quicker than any other spectrum in our aquarium bulbs. If you get something that will emit that spectrum with others (such as the 14000K bulbs or higher) The blue spectrum will kick over before anyother spectrum. (the bulb will still burn however, the blue spectrum will just not be strong enough to penetrate the water.) So again, to make my babbling alot simpler. If you go with the 14000K bulbs youll still have the pretty much equal spectrums as a 10000/flourescent combo, but you will change bulbs way more often. Whereas with the flourescent combo you can simply change out the actinic flourescent bulbs more and leave the halide bulbs on longer. (flourescent bulbs are way cheaper than halides.)

hope that made sense.

 

[Tackett]

Len, I think 14KK bulbs emit the blue spectrum. Although i could be wrong, im sure ive seen the wavegraph somewhere...

 

[Len]

Yep, I'd need to see it. I've seen Hamilton 14KK that look like 10KK to the eye. I've seen 13KK look like 20KK to the eye (confirmed by Sanjay's spectral analysis in www.advancedaquarist.com). So as you can tell, Kelvin ratings are rather random.

 

[Tackett]

true true

 

[KoCook]

If your going for 250s, get the DE HQI. I just got two 150s with PFO pendants (I already had 220 pcs that use to be the mains but just weren't cutting it, now they're the dawn/dusk) Go with the 20ks, they might go faster but I've found that the life expectancy of bulbs is random anyway. Heck, my pc bulbs were almost bad brand new (the cheapys) The blues are so much prettier, not to mention they penetrate the water better SmOkIn........

 

[dab1]

Thanks all for the replies. Intelligent discussion is exactly what I was after and what you have provided. Now I just have to get busy and order some lighting. Ain't cheap...