Light question help

what size tank???? (probably not though) I think a 4 bulb would be better....but need tank size

YEAH...at least 4 then....I have a Sundial T5HO on my 29G...and I have a derasa clam that is doing great....but it also has 4 bulbs....I really think 2 bulbs on a 40G is too little.......

since it is a 40 breeder, i would suggest having one of the better fixtures (ati, tek, aquatinics) if you plan on having the clam on the sandbed. if you can put it in the rock formation, a current usa fixture should hold it fine as long as theyre the contoured reflectors. Keep in mind that with these, you would still need the better bulbs

you can prolly keep lps and zoas with just those 2 bulbs. for a 18" wide tank, youd prolly want something like 6 bulbs just to get the spread and get everything covered. the nova extreme pro + ATI bulbs/KZ bulbs would be sufficient for you to keep clams if you had them in the upper 2/3 of the tank

4 bulbs is a must to keep clams and sps.

I've had a derasa clam in my 40G breeder for about 11 months. It is doing great under 4x39w T5 HO lights. It has doubled in size, from around 2" to around 4" now...Get the 4 bulb fixture, you won't be sorry!

2 39w T5 HO + 40 GALLON breeder = No.

If you were dealing with something in the neighborhood of even 3+ times the tanks size in wattage, then maybe.

I'm setting up a 65Gal (36"w 24"h) and have a 36" dual 96watt power compact.  The current bulbs in it are a 10,000K and a 420/460nm. Picked it up used for $50, with 3months on the current bulbs.  Thinking of replacing the bulbs after the first few months before getting into big invertebrates, if I can get by with this fixture vs buying a new one.

 

I was hoping to eventually get a Derasa. Should one be ok atleast in the upper half of the tank?

 

Long-term under PC is doubtful.
 

A derasa needs to be in the sand. It is not a rock dwelling clam.

 

Wango is correct, long term, it will not do well under that amount of PC lighting.

 

 

I have successfully kept clams under PC lighting, but they need more than what you're offering.

oah well that sucks. 

 

I know you guys are referring to Halide to use for clams but why does everyone always seem so down on PCs and up on T5? I figure they are both flourescent tubes so watt for watt wouldn't output be similar?

You can keep clams under T5's as well, even PC's is possible, but it all depends on the PAR. A 100 watts of PC lighting produces less than 100 watts of T5, which produces less than 100 watts of Halides. I'm not a lighting expert, but basically it has to do with how the lighting is able to travel through the water and how far it is still effective.

 

PC's are really only good for fish only and soft coral tanks. They just do not provide enough light for many corals. Keep in mind that most corals have algae living inside of them (zooanthellae) that keeps the coral healthy. This algae, like any algae is photosynthetic, and needs the strong lighting to keep it healthy. If the coral is not provided with strong lighting, it will release the algae and die. The same is true about colorful clams, they feed off the light. PC lighting is not as much like natural sunlight as T5 and halides are.

You also need to remember that most reefs are fairly shallow, so sunlight can really travel through the water to reach all the organisms that require it to survive.

 

PC's work fine for fresh water setups and fish only setups, because the sunlight requirements are much less.

 

If you plan on keeping most corals or clams, you're going to need a good T5 setup or metal halides.

theyre both flourescent but theres no comparison in the par output. pc's par drop rapidly once it tries to penetrate through the water