380w or 442w for 40g?

[modernmagic]

I have a 36x15x17h 40g tank. I plan to have mostly soft corals and some clams and fish.

Aquatraders . com sells an Odyssea 36" 442W Metal Halide System with Power Compact AND a 380w version.

Which one should I get for my 17" high 40g tank?

[charlie]

Welcome to Reefland.

In my opinion, if all you are going to have is softies, either one of those 2 is way overkill. Try looking into a 36" T5 fixture and you will save money and not boil your tank. Jmho

Do a search on what folks are doing with T5 lites these days. either a 4 or 6 bulb fixture is all you are ever gonna need.

[gregony]

Charlie's right,
I use a 6 lamp Nova Extreme Pro (224W) for my 40g tank which is the exact same size as yours and it will burn soft corals to a cinder. It works great for SPS, and to be honest, its not necessary for those even. I was kind of like one of the first people on the block to take the T5HO plunge so I bought one based on the now outdated 5W per gallon formula. Avoid power compacts, they are being obsoleted by T5HO. A 4 lamp Current SunDial or AquaticLife (both have built in timers and individual reflectors) would probably be more suitable for your desired livestock. Heck, a 2 lamp fixture would probably be fine for softies. I don't know that you can keep softies and clams in the same tank (if its a small tank like a 40g). Maybe Charlie or someone with more mixed livestock experience could chime in on that front.

[charlie]

Softies and clams are fine together. One word of concern tho, make sure you do your research on what clams you are going to get, some do require more light than others, maximas and croceas would fall into the higher lite category.

[modernmagic]

ok charlie.

so I take it 36" T5HO are 39w. So 4-6 bulbs would be 156w-234w. I only need 156w? Why do they sell 442w 36" fixtures then?

I forgot to mention, my brother is making a wood canopy for the tank. So I planned on not having the fixture close to the top of the water. If the lights are 8-10" above the water will this require more or different lighting?

thanks for all the advice

[charlie]

Forget the watts per gallon, and do a search on PAR value. Much more important. WPG is an antiquated way of doing things these days.

[modernmagic]

PAR does not show up in reefland searches. google gets me a definition but not exactly how to use it.

PAR (Photosynthetically Active Radiation)

Now what?

[charlie]

Like Greg said, go with a T5 fixture, you will be able to have anything you want, Check the sticky in this forum to Sanjays site, he explains PAR rather well, better than I can.

[MyNameIsJoe]

You might also want to check out the thread titled "Thinking of getting t-5's? Read this...
" it had a link to a comparison of the different t5ho brands. Not sure how Valid the info is, but it sounds legit and will give u something to go off of. I have (had) t5ho's and they were working great and lit up the tank nicely.

Joe

[gregony]

Been away a week. Why do they make 442W 36" fixtures? Remember, they make 10 foot long tanks. They make 6 foot long tanks. They make tanks from 12" deep to as deep as you want. Manufacturers make fixtures to accomodate the needs of a wide range of consumers. Believe it or not, they make 80g and 90g 36" wide tanks. I wish I had the money for one of these as I really like 36" wide tanks. Don't forget the larger hex tanks too.