Even if you don't "need" actinic to soften your lighting, it is a plus to run on a separate timer for dusk/dawn lighting. I'd never be without it, as it allows for a slower transition to night/morning, which is natural, plus a time for viewing different tank activities.

Thanks teevee!
I'm blushing. :oops:

Please keep me informed on how your hood construction comes along and some pics if possible would be great.

The most favourite part of my tanks day is when the halides go off in the evening and the actinics are on for 2 hours or so by themselves.
I would run actinics with 10k bulbs.

sounds good folks. you seem to feel so strongly about actinics, i'll look into it then. i agree that providing a more natural cycle would be nice.

It depends on the ballasts that the fixtures use, but remember that some ballasts can run both halide bulbs and mercury vapour. If the ballast says M57/H35 then it runs 175W bulbs of both types, M58/H36 then 250W, etc. etc.

Your correct Tony,
But those ballast's are unfortunatley the more expensive of the halide ballast's that you can get from local light suppliers.
The "multi purpose" ballast that you speak of are around $90 to $100 which is what I was quoted recently when I was looking into my halides.

:shock: Wow, when Home Depot was selling them, they had them vfor $50 or $60, when they decided to stop selling them they unloaded all their stock they did so at $30. No wonder they suddenly flew off the shelves!!

I actually was thinking that maybe the MV fixtures for 175W at HD, were using those multi ballasts. Maybe not though, considering the fixtures are only about $100 or so.

...

Just one additional food for thought. I'm sure I've read somewhere that Iwasaki bulbs are not recommended for use on "combination" ballasts. I have no idea what "combination" ballast means. What worries me, is Iwasaki's are a special case. You can run them on a mercury vapour ballast, you can run them on a metal halide ballast ...... so why shouldn't a "combination MH/MV ballast" not be perfect for these bulbs?? I should mention one of my ballasts for my 75g is one of these ballasts. The other is a used MH ballast I got from hydroponics store and I never opened the casing to see what kind it is (m58 or m58/h36). I wonder if I'm doing damage by this?

I guess I should probably write Iwasaki myself and ask them this question. I should look for some tech support contact info I guess...