is this deep? i am confused

[marinefish]

what is consider a deep tank? my 20 gallon is about 18inches deep. but from teh top of the sand to the surface of the water is is about 15-16 inches deep. i have 144 watts of power compact light on my 20 gallon. i was told i cant keep a maxima clam because it wasnt enough lighting. the thing is when i searched the info on maxima clams, they had indicated that maxi needs about 6-8 watts of light per gallon in a not deep tank. so am i right to assume 15-16 inches deep tank is consider deep? if not then would i still be able to keep a maxima clam? i am confused. please help, anyone??

 

[cjburden]

I'd say that you are very borderline, however being that you have PC's and not MH's the clam probably will not thrive in that lighting. So could you keep one? yes, but it probably won't grow a lot and it won't be as vivid a color as you see in pictures of ones under MH/actinic combos.
I'm by no means whatsoever an expert on clams OR lighting but from what little I DO know thats what I'd think.

 

[marinefish]

hum...i was planning to try a maxima about half way up the tank or towards teh top of the tank since i have my rock work structure like a shelf in two different levels. with 144 wats of light and placing the clam between half and top of the tank is still not enough lighting? sorry to sound redundant, but i am kind of confused. since metal halides are designed to penetrate deep water tanks, is my 20 gallon tank consider deep?

 

[pmauro]

I don't think it may be the amount of lighting as much as the lighting spectrum output from the pc versus the MH lighting. that would be the difference in the clam living, or thriving in your tank

 

[broncofish]

I have seen clams grown under light other than MH's. It is not the MH that matters it is the kelvins. There are a lot of people out there that don't like MH's. The big benefits to the MH is a lot of output in a small space, and I have to admit that being able to pump up your watts to 500 with only 2bulbs and one ballast is cool, but IMO @ 7.2 watts per gallon, with the correct color spectrum(I am assuming one bulb is 10000K, and on 50/50) and placing that clam halway up your tank you should be fine. Fine being the key word, not thriving and beautifull. The best looking Clams I have ever seen were under VHO's(440watts on 55g). Just my .02 though