Clams, lighting, bulb temp

[george]

Work with me on this theory and let me know your thoughts:

Assertions:
1. Clams love light.
2. Clams feed on nutrients in the water column.
3. Clams have symbiotic algae in their mantles.
4. Algae grows better on light in the 5000K - 65000K spectrum than the 10K(K)-20K(K) bulbs we use over our reefs.
5. Refugiums are intended to take up nutrients from the water column.
6. Refugiums work best under 5000K - 6500K spectrum to help with algae growth.

Theory: Would a hardier clam such as a Derasa do well in a refugium under 5000K bulbs?

The refugium in question is not a small one like in a sump or hang-on, but a 15g (eventually 25g) tank.

My intention is to have a fully functional refugium, but also make it an aesthetic addition to the display, not merely an organic cesspool.

 

[mojo]

They'll do fine, as long as they have enough light....

 

[jmaneyapanda]

And you probably wont get to appreciate their beauty as much as if they were in the display. Some people do try to use "steamer" clams for this purpose. I'll see if I can dig up the info I saw on that.

 

[george]

Unfortunately, I can't find a PAR rating on the bulbs I bought, but they're 800 lumens, 20 watt PC bulbs in floodlight bulbs (i.e. they're packaged like incandescent floods) similar to the ones Marc Levenson mentions in his log (http://melevsreef.com/fuge_bulb.html)">http://melevsreef.com/fuge_bulb.html)</a>, but they're "90 watt equivalent" which I think merely means that the bulbs are the same size as 90 watt incandescent bulbs.

Water depth after the 5" DSB in the fuge is only about 6" though.

 

[mojo]

You won't find a PAR rating on any bulb - there are too many variables that come into play for any given setup (ballast, bulb life, distance, calibration technique, etc, etc).

"90 watt equivalent" means that these 20w bulbs will give off about the same amount of lumens that a 90w incandescent bulb would give off.

I'd go with jmaneyapanda's suggestion and use clams that are typically used in the food industry. You can get them much cheaper and they'd be just as effective.

However, do keep in mind that you'll have a really hard time beating what you can do with macro algae. Think about it in these terms - you want to remove a certain amount of nitrate and/or phosphate from the system in this fuge (if that's indeed its purpose). You want to look for whatever grows the fastest that will accomplish this (and thus by doing so, will convert those nitrate or phosphates into something you can remove or otherwise no longer usable by the system, say in a clam mantle). The fastest way I know how to do this is chaeto macro algae.

 

[george]

These are http://atlantalightbulbs.com/ecart/10Expand.asp?ProductCode=FE-R40-20W.50K">the bulbs</a>, but they can be bought singly in the Atlanta Light Bulbs stores.

The refugium should be quite viewable. Probably easier to look at them top down since they'll only be in 6" of water. The Derasa's in question are ones I already have. They're just getting a bit large for my current main display. They've lived fine under a 96w PC fixture that was 50/50.

 

[washowi]

I have "Little Neck Clams" in my tank..Bought them from Harry's Farmers Market for like 6 for 75 cents

 

[george]

I'm not interested in the clams as filtration machines. As Chris pointed out, cheato is way more efficient. I was just thinking that the wide open sand bed would be a nice place to put them, but I was concerned about the bulb spectrum affecting them.

I'm reasonably confident in it to try, but wanted to see what others thought.

 

[fishybusiness]

Smaller clams at least the tridacna sp. </em>clams as they are smaller are more filter feeders than they are photosynthetic. This is why some people have more luck with buying larger clams (over 2") as opposed to the smaller ones (under 2"). Can't remember where I might have read this but it seems to make sense. There was also comparisons as some of the different species tended to be more photosynthetic than others.
Many years ago I ran some maxima clams under a 5500 k 150 watt metal halide and one died within a week but I had the other for a while. They looked like crap untill the actinics came on.
Ive got freshwater plants growing under screw in power compacts though. bought em at home depot in the plant section with some decent color liked them better than the flood lights that were in there.

 

[george]

FishyBusiness wrote: This is why some people have more luck with buying larger clams (over 2") as opposed to the smaller ones (under 2"). Can't remember where I might have read this but it seems to make sense.

I have been told by two different dealers that sub-2" clams lack sufficient mantle surface area to create all their nutritional needs by photosynthesis alone.

 

[jmaneyapanda]

George- this isn't true- it's kinda an old wives tale. There is a new book out by James Fatheree that addresses this in depth. I have talked with him, and he provided me with a few scientific paper which debunk this claim.
Clam do filter feed, but do not require to be fed. They provide more than adequate sustainance to survive, and even grow in certain species, solely from the zooxanthellae i their mantle. Let me know if you want the info on the papers, I'll dig that up too.

Smaller clams die because smaller ones are more delicate and subject to environmental swings than larger ones.

I would suggest stronger lighting than you mention, but I am not familiar with that bulb or fixture.