yet ANOTHER lighting question

[pepe.king.prawn]

Hey. Not my first tank, but I'm on the fence here. I have a 40 gallon with a built in wet dry(19" tall x 36" long) that I've got setup, so now I'm looking at my lighting options. I'm going to go with 20k bulbs so I can get the sps coloration I want, but I'd also like to be able to keep clams on the sandbed.

I have a dual 175w ballast sitting around, but I need reflectors and new bulbs which totals $177. For slightly less ($170) I can get an entire new 250w SE setup with ballast, bulb, reflector and all, and I could sell the 175w ballast to recoup some of the cost. Would this 250w bulb be sufficient? I know the 2x175 would cover the length of the tank better, but I don't want to have too much light to keep sps near the top of the tank. Thanks for your help, and happy reefing!

 

[mbbuna]

Clams come from shallow water, where they get a full spectrum of light. 20k bulbs replicate a deeper water water environment then clams come from. some people keep clams under these bluer lights, and some have problems. for clams i would recommend 6500 to 10k.

 

[llewoh05]

don't mean to steal your thread.

for a 10gal.(8in. tall) with low-med light 30-40watt. is there any clams that i could keep?

 

[Peabody]

No on the 10 gallon.

 

[pepe.king.prawn]

Well, I know that clams can survive under 20k's, as I know 5+ people that do so, I'm just wondering if the intensity is sufficient. 6500k bulbs may look bright, but intensity bares no correlation to the absorption spectra of clorophyll (primary photosynthesis) in zooxanthellae, which is primarily blue and lesser red. Carotenoids, another photosynthetic component in zooxanthellae can utilize green-yellow light. Anyhow, I'd just like to know what you guys think intensity wise, not really lookin' for opinions on spectra. thanks.

 

[Ti]

I had clams under 20K

 

[pepe.king.prawn]

lol.. Ti being one of the 5.

 

[Ti]

 

[mbbuna]

<a href=showthread.php?s=&postid=6740294#post6740294 target=_blank>Originally posted</a> by pepe.king.prawn
Well, I know that clams can survive under 20k's, as I know 5+ people that do so, I'm just wondering if the intensity is sufficient. 6500k bulbs may look bright, but intensity bares no correlation to the absorption spectra of clorophyll (primary photosynthesis) in zooxanthellae, which is primarily blue and lesser red. Carotenoids, another photosynthetic component in zooxanthellae can utilize green-yellow light. Anyhow, I'd just like to know what you guys think intensity wise, not really lookin' for opinions on spectra. thanks.

you asked about 20k lights for clams but dont want any opinions on spectrum

clams have certain needs and spectrum is on of them. nowhere did i say they couldn't be kept under them. just that some or i should say more people have light related problems with clams when they are using lighting that is of an unnatural spectrum like 20k.

forgive me but im a little confused about your last post.
you say.

I'm just wondering if the intensity is sufficient.

then

but intensity bares no correlation to the absorption spectra of clorophyll

then

I'd just like to know what you guys think intensity wise,

i think i know what you meant to say but??

there's more to photosynthesis then focusing on one blue band. especially when the organisms you want to keep depends on multiple species of zoox all with different spectral preferences