What PAR do you like for Derasa Clams?

[campaign000]

I prefer to hit them with a good deal more than minimum at the very least, to be on the safe side. My sandbed clams get 250-300, my middle up clams get close to 500, happy as can be, just less mantle extension because high flow and light.

Great! What kind of light are you using? Could you put pic of the tank?

 

[Shigshwa]

Great! What kind of light are you using? Could you put pic of the tank?

Atlantik V4. It's too blue for my liking, more of a fairy tale looking light blue, but it sure grows corals!

 

[Shigshwa]

Bonus 10 inch derasa pic.

 

[DesertReefT4r]

I don't believe clams need to be fed no matter the size. It won't hurt to dose live phyto here and there but direct feeding is not necessary. Also, par has a lot more to do with just growth rates. Keeping a maxima low in the tank at 200 par isn't just going to make it grow "slower", it will need a lot more par to thrive. @jda do you have any par recommendations? Plus, the quality of light also matters as well.

I agree, I only spot feedmmy clams phyto in my earlier days. Once I stopped I never had an issue keeping clams healthy and growing. 150 PAR would be my personal min.

 

[Tft12]

Growth has been good so far.

 

[hart24601]

Growth has been good so far.

Wow that is some great growth. Nice job!

 

[Tft12]

Nice job!

Thanks. I had been a little worried because I'm using a somewhat low-end LED, with PAR being towards the lowish end of recommendations, and I tend run nitrate and phosphate significantly higher than most people would say is ok...but doing well.

 

[hart24601]

Thanks. I had been a little worried because I'm using a somewhat low-end LED, with PAR being towards the lowish end of recommendations, and I tend run nitrate and phosphate significantly higher than most people would say is ok...but doing well.

Just so we have another data point what is the PAR you have it in along with phosphate and nitrate? FWIW I have found smaller derasas at least it be ok under 100 PAR for the duration of the photoperiod and end up closing by the end of the day (really in a couple hours) with 200 or more PAR, however it's possible the PAR demands change when they get really large. Also there is apparently individual differences with the same species, but clearly you are good! I personally know people that have kept derasa with the big t12 fluorescents alone in really nutrient rich tanks but I rarely say that as I don't want to seem that I suggest it!

 

[jda]

It is likely the ammonia and ammonium that the clam gets fed from, not N or P. N and P are building blocks, not sources of true nutrients for most organisms. However, tanks with N and P probably had ammonia and ammonium floating around as well, but tanks with high N and P because of low export that will have low feedings and low ammonium probably will not be OK.

 

[Tft12]

Just so we have another data point what is the PAR you have it in along with phosphate and nitrate?

PAR is around 200 at the sand bed. Nitrate is around 40 ppm and phosphate is around 1.3 ppm.

To @jda’s point, my system receives massive feedings many times a day so it would tend to be on the high end of nutrient levels due to high import rather than low export.