wattage guides

[PsychoKnight]

When I hear and read people talking about so many watts of MH per gallon capacity, it seems to leave out the supplemental actinics wattage.

Is this an omission, or am I supposed to include my pc actinics into total wattage. Or, is it that actinics are such a minor supplement, such that more or less is inconsequential?

I would like the option of keeping any type of coral near of the bottom of my 20" tall (+11" bulb above water). I have a MH ratio of 4.54w/gal and actinic ratio of 2.36w/gal, totalling 6.9watts/gal. Will this be sufficient on a 36x18x20 allowing me to keep even the most light-demanding corals?

Thanks,

PK

[evolution]

What is the wattage of the Halide you have?

My tank is similar in dimensions (actually about 10 longer) and I am running a 250w and a 400w. This gives me about 8wpg but I think I may drop it down to 2 250w bulbs which would give me 6.25wpg. It seems that you could get away with 1 400w and never worry about not having enough light. You should be alright with the 250 but make sure you place your SPSs accordingly as they are the only heavy light demanding corals. They should be in the top third of the tank.

...and yes, actinics are supplimential. I dont include them in the total wattage because they do not promote growth... IMO at least.

[dpstrand]

I'm trying to decide on lighting also, but what I've picked up from reading and reading and reading is it really depends on what you want to keep. If you are keeping SPS and using Halides then with a 20" depth you probably want 250s over it. If you are not keeping SPS then I really think 250s are overkill and in fact probably make it harder to keep lower light demanding corals.

I don't see much info on how much actinic you should have to compliment the MH, but it seems that it's mostly for looks so if it looks good then stick with it.

[exoticaquatix]

ill have a 400 watt 20k over my 65 gallon tank. its a 24 in deep tank so ill need the intensity and im going with a 20,000 k so i dont have to mess with PC's in my canopy. is this a good idea? or should i use a 10 or 14k with actinics?
im planning or doing SPS corals (have not before) so i want to have strong lighting but i would also like to have some zo's and LPS corals in there too. is that too much for them or can i just shade them with my rock work? im guessing thats fine.
~nick

[evolution]

You will see the best growth (and asthetics) with a 10k Iwasaki supplimented with actinics. The bonus to actinics are a "ramp" ,into and out of, a photoperiod.

Plus, I just yanked my 400 and replaced it with my old 250. I think the 400 was a 6500K and looked like crap. The 250 10k looks twice as bright, much more natural.

[PsychoKnight]

I have the option of installing any combination of 175/250/or 400 (have a bulb & ballast for each wattage) into the hood assembly of my 20" 55gal "G" shape.

I'd like to be able to keep my options open for SPS & clams on the bottom. I plan to use a 250w 10K along with 175w of actinic pc. Although most people don't count actinic wattage, I see several LFS which use actinic exclusively (no, not 50/50 or 20K, I asked) with very good long term results, so I have to assume that actinic power should count for something. I'll try it this way first and see what happens. If the SPS and clams don't look vibrant, I'll switch to the 400 bulb & ballast.

Also, a retailer told me that clams less than 4" don't have enough phyto-cells and require supplemental live phytoplankton feedings. Is this true?