Squamosa PAR?

[MartinM]

So I have 16 shallow water clams that all get 400-700 PAR, but I’ve never had deeper water clams like Squamosa or Deresa before, and I just got one of each. I’m getting 225-250 Par on the sandbed but I’m worried this is too low. Can anyone chime in who’s had one of these for 1+ years and what PAR they’ve been at for that time? Thanks!

 

[minus9]

Here's the thing about tridacna clams that we keep. They all inhabit shallow waters and are exposed to intense lighting, but some can live in slightly deeper water. I've never considered clams as "deeper" water or "low light", I think this is the wrong way of thinking. They are extremely adaptive, but some like crocea, maxima and noae are not adaptive to lower light. I think with derasa and squamosa, you can keep them at that level (250 micro moles) and they should be fine. I've seen both in slightly less intense locations and they grew just fine. As you know, just look for new shell growth and you're good.
I can't find the video now, but there's a video during low tide, where derasa and squamosa clams are completely exposed and you see them closing up and shooting streams of water as they pump water from below their intake siphon. Also, derasa and squamosa that are found in deeper water (10-15m) are in super clear water, so the lighting is still intense in those locations.

 

[MartinM]

Good points - I’ve seen maximas and crocea exposed but never seen a Squamosa in less than about 6m. That being said, you’re right, water was clear.

I’m not comfortable with any clams at 250 which is why I asked. I’ll lower the fixture a little on that side for more PAR!

 

[cdw79]

I keep a derasa at 250 par and it's had great growth, no supplemental feeding. You should be fine with it, at least

 

[HudsonReefer2.0]

My squamosa 8months in. Lights out. FTS from before. Xl300 w 2x Xr 15 g5 pro ab+ 90% intensity for solid 10 hour pp. I’m happy with results. Before that had a considerable derasa.

 

[MartinM]

My squamosa 8months in. Lights out. FTS from before. Xl300 w 2x Xr 15 g5 pro ab+ 90% intensity for solid 10 hour pp. I’m happy with results. Before that had a considerable derasa.

I didn’t see your PAR listed?

 

[HudsonReefer2.0]

I didn’t see your PAR listed?

Don’t really know it thats why I provided lighting info or type photoperiod and intensity. Works for what I have so if u have a similar set up then should b good. Short or long term. Happy Reefing

 

[Troylee]

I didn’t see your PAR listed?

Par is horrible on radions.. I bet it would say like 70-100 at best in his tank.. them lights grow corals really well no matter what a par meter says.. ! I have 3 myself and ran just a single xr15 on a 60 gallon cube and could grow anything I wanted any where in the tank..

 

[HudsonReefer2.0]

if needed I was able to source some g5 xr30 pros. But the xr15 ok for me and the metabolic needs of the corals and clam

 

[MartinM]

I moved the deresa to ~450 and Squamosa to 300ish.

 

[Spare time]

Par is horrible on radions.. I bet it would say like 70-100 at best in his tank.. them lights grow corals really well no matter what a par meter says.. ! I have 3 myself and ran just a single xr15 on a 60 gallon cube and could grow anything I wanted any where in the tank..

They have a very wide blue spectrum which in a way compensates for lower par as its more 'power per par'

 

[MartinM]

They have a very wide blue spectrum which in a way compensates for lower par as its more 'power per par'

The term is 'PUR' (photosynthetically useable radiation), and different species have different abilities to use the blue part of the spectrum. Clams are not one of the species found in deep water where the spectrum is predominantly blue shifted. PUR varies among species, and even individual animals.

The definition of PAR includes the entire spectrum of visible light, so therefore no matter whether 'blue heavy' or not, a PAR meter will accurately report PAR. As an example, if PAR is 100, no matter the light source, it's insufficient to keep clams. Unlike PUR, PAR is a standardized measurement of mmol/m-1, a measure of energy. There is no such thing as 'this light puts out X PAR but can still grow species that requires X+50 PAR, because <insert contrived reason here>".

 

[Spare time]

The term is 'PUR' (photosynthetically useable radiation), and different species have different abilities to use the blue part of the spectrum. Clams are not one of the species found in deep water where the spectrum is predominantly blue shifted. PUR varies among species, and even individual animals.

The definition of PAR includes the entire spectrum of visible light, so therefore no matter whether 'blue heavy' or not, a PAR meter will accurately report PAR. As an example, if PAR is 100, no matter the light source, it's insufficient to keep clams. Unlike PUR, PAR is a standardized measurement of mmol/m-1, a measure of energy. There is no such thing as 'this light puts out X PAR but can still grow species that requires X+50 PAR, because <insert contrived reason here>".

I disagree. Its is not an issue of how deep an animal grows, but by what par value hits photosaturation. It should be easier to hit photosaturation under a wide blue spectrum than a more varied spectrum with distributed power. Photopigments have certain wavelengths where the electrons in PS2 are most easily excited. So
"50 par" of blue provides more energy to the coral than "50 par" of orange because nearly all coral photopigments peak in the bluer range. I don't like PUR because I think its not a useful number since different organisms have different photopigments. It is similar to how something like 100 calories of mushed food provides more energy than how 100 calories of solid whole food.

 

[MartinM]

I disagree. Its is not an issue of how deep an animal grows, but by what par value hits photosaturation. It should be easier to hit photosaturation under a wide blue spectrum than a more varied spectrum with distributed power. Photopigments have certain wavelengths where the electrons in PS2 are most easily excited. So
"50 par" of blue provides more energy to the coral than "50 par" of orange because nearly all coral photopigments peak in the bluer range. I don't like PUR because I think its not a useful number since different organisms have different photopigments. It is similar to how something like 100 calories of mushed food provides more energy than how 100 calories of solid whole food.

These things are not matters of opinion, they have specific definitions. Go hit up scholar.google.com

 

[OrionN]

So I have 16 shallow water clams that all get 400-700 PAR, but I’ve never had deeper water clams like Squamosa or Deresa before, and I just got one of each. I’m getting 225-250 Par on the sandbed but I’m worried this is too low. Can anyone chime in who’s had one of these for 1+ years and what PAR they’ve been at for that time? Thanks!

I agree with @minus9, I keep my Gigas, Derassa and Squamosa at the same light level at my Maxima, Noae and Crocea. they are doing great.My gigas was 24 inches (from a 2 inches baby) until a hurricane stupid mishap killed it.

 

[MartinM]

I agree with @minus9, I keep my Gigas, Derassa and Squamosa at the same light level at my Maxima, Noae and Crocea. they are doing great.My gigas was 24 inches (from a 2 inches baby) until a hurricane stupid mishap killed it.

Thanks!

I remember the hurricane and your mishap . I've had similar stuff happens, it's the worst.

 

[minus9]

I think when people hear that some of these clams are found in slightly deeper water, they think it’s much deeper, but that water is crystal clear and the amount of light is still intense. And we’re only talking about a 5m difference between the shallows. Most of the these clams are found 15m less.