Tridacnid Clam Lighting Article  3/16/11
A good article on the subject by James Fatherree.
http://www.advancedaquarist.com/2011/3/inverts
James
<As usual. BobF>

Maxima Clam and Light Upgrade -- 03/18/10
Hello my name is Brice and I have had 75g reef tank for about a year now.
<<Greetings Bryce>>
I have a 3-4 inch Maxima clam in there that is doing great, showing lot of growth.
<<Excellent>>
I keep him about 4 or 5 inches under the water with a 150w MH about 8-10 inches over him.
<<Mmm, yes'¦a 'light loving' species>>
I just got a great deal on a 250w MH and moved it over him and moved the 150 down to the other side of the tank.
<<Hopefully you took step to 'acclimate' the clam to this new lighting>>
I am currently diffusing the light with sheets of eggcrate
<<Ah! Very good>>
and plan to do this for a few weeks.
<<Removing a sheet every few days until all are gone should be sufficient>>
I run my white lights about 12 hours per day which is probably too much.
<<Mixed schools of thought on that. I don't think it hurts'¦there are those who even think an extended photo period (to a point) can make up for 'some' lack of intensity 'but your livestock can likely get by very well on a 9-10 hour photoperiod if you wish to make a change>>
I just wanted to know if this will be too much light for the clam only being about 14-15 inches from the 250w MH, or if I should move him lower.
<<Observe the clam to be sure (if it fails to open/expand fully under this lighting then there could be a problem), but this species of Tridacna should handle (even love) this amount of light just fine>>
The bulbs are 14k but I would like to upgrade to 20k bulbs, would this be too much blue light or do you think I have enough wattage over the tank to be sufficient.
<<The 20K is not my cup of tea, but under this wattage and at this distance it is probably okay here 'again, observe the clam to see what it 'thinks' of it>>
There is a total of about 650watts with the two MH and my PC's
Thanks, Brice
<<Happy to share'¦ EricR>>

Lighting for SPS and Clams -- 01/27/10
Hi,
<<Hello>>
I just got a custom 75 gallon aquarium; the dimensions are 24"W X 30D" X 24" H.
<<Interesting dimensions 'the long depth should make for a very interesting 'view'>>
I plan on having a 6" deep sand bed, so the height will now be around 18". I would like to know what type of lighting will be best if I plan on keeping SPS and clams.
<<My fave is metal halide 'though you could make T-5 HO work here as well>>
I will not run a chiller, so I'm wondering if a 150 watt MH will be enough?
<<Possibly 'with a good reflector>>
My other option is 2 X 65 watt PC, with a 70 watt MH.
<<Mmm'¦this combo will likely give you better 'spread,' but may prove marginal for very high light-demanding species (e.g. -- Tridacna crocea). Much will depend on placement of the livestock. A higher wattage unit will give you more flexibility re>>
I have a 250 watt MH but I feel it might be too much.
<<Not at all 'in my opinion>>
Can you please help me figure out which will be best?
<<For what you want to stock in this tank, I would use the 250w MH. Suspended above the tank in a 'large' quality reflector like the Lumen Max Elite from Sunlight Supply, or even the Lumen Bright from CoralVue, would make for a very striking display. The 250w lamp also gives you some flexibility re adjusting the height of the reflector up or down to control temperature or light intensity as/if needed>>
Thanks
<<Happy to share'¦ EricR>>

T5 lighting question Lighting Requirements/Tridacna Clam 2/4/09 Hey gang, <Hi Alex> Quick question regarding T5 lighting, I recently bought a 30" 4X24W HO Sundial T5 fixture, two 10,000Ks and two 460 actinics. Now my question is will this be enough lighting for a Tridacna clam...say a Derasa? <The T5 HO's will work for the Derasa but I would keep the clam no deeper than 12 inches from the water surface.> As I bought a 3" Derasa clam about a week ago and I was told that it should be fine under my current lighting...a Corallife 24" Aqualight Deluxe 130W PC, <I'd use the Sundial T5 fixture you bought. Will be a little more intense than the PC's. The T5 fixture you have is equivalent to about 190 watts of standard fluorescent lighting.> now I have read and reread many times about the lighting requirements and have found very mixed reviews on PC, MH isn't really an option for me, and have found many people having success with HO T5's. <I have heard same, but the T. Crocea does best under MH lighting, but has been kept successfully under T5 lighting providing it is kept near the top of the tank and the fixture is of sufficient wattage.> My tank is a 29G with a Flame Hawk <Tank too small for this guy.> and Purple Firefish, couple of small hermits, sandsifting starfish, and a few trumpet corals, GSP, Duncan coral, and some Anthelia. I know Derasa's can get around 20" but I have a 125G that I could relocate it when the time comes. <That time is going to be long in coming. Under natural/ideal conditions, the average growth rate is 1 to 2 mm per month. In captive systems, likely less.> The clam is currently on the sandbed approx 14" from the light. <Too deep, I'd move the clam up and get that T5 system up and running.> I have even heard of people keeping Crocea's under T5's...is there and truth (long term) to that? <A good article in regards to keeping the T. crocea can be found here. http://www.reefkeeping.com/issues/2007-10/jf/index.php And Tridacna in general here. http://www.wetwebmedia.com/tridacnidart.htm and here. http://www.wetwebmedia.com/ca/volume_4/V4I3/Tridacna/artGotTridacna.htm> Tank water parameters are all reef ideal, with the exception of phosphates....8ppm Thanks much, <You're welcome. James (Salty Dog)> Alex

Re T5 lighting question Lighting Requirements/Tridacna Clam And Not Reading 2/5/09 Hey gang (again), <Hi Alex. Since this is a continuation of a thread started yesterday, we ask that you reply with the original thread. In that regard we can see what has transpired.> Ok so the 30" sundial T5 HO 4X24W will work for Tridacna clams depending on type and location in the tank. <Yes.> I have the 29G that currently houses a 3" Derasa that upon James "salty dog" (thank you very much for the advice btw) I have moved <the clam> up to about 8" from the light. Now my new question is, with individual reflectors would this be able to house a crocea clam? <Lighting information/requirements are stated in the James Fatherree link I gave you yesterday. Did you read it?> I read that 10,000K's would be best for a crocea and am just wondering if I switched some of the bulbs what combination would work best for a crocea, or any other Tridacna for that matter? <The choices in Kelvin temperature in T5's are pretty limited right now. To my knowledge a 6.7K, 10K, and 12K are available. In your case I'd go with a 3 to 1 ration of 10K and actinic. The 10K is going to give you a little more PAR value than the 12K.> The crocea is not in the near future but more of a fluttering hope. Or would I need another bulb or 2 on the tank to keep it happy. I want it to be healthy not healthy enough to live. and MH are really out of the question, otherwise I would have them. <All stated in the Fatherree and Got Tridacna link.> thanks again for your expertise, <You're welcome. James (Salty Dog)> -Alex

Clams -- Lighting 12/31/08 I have a 50 gallon reef tank with mostly LPS and softies. I recently upgraded to a 2 x 150w HQI Metal Halide fixture. I read your FAQ on Clams and decided that I should start with a T. Derasa as they are one of the easier to care for clams. I maintain good reef conditions (Nitrates >10, Salinity 1.026, Ca >400, KH 10-12). Will my 2 x 150w fixture be enough to keep a Derasa and other clams in general. Also is this fixture good for SPS such as Acropora ?  Thanks Henry Aspegren <Two 150s will serve you well for all of the above on a 50 gallon. Welcome, have fun, Scott V.> Re: Clams -- Lighting thanks <Welcome, enjoy the system. Scott V.>