Crocea lighting

[FINFISH]

I've got a 250watt 10k DE HQI lamp with two 24"T5s (blu, blu+). The tank depth is 24" (36longx24w) and the lamps are about 6-8" above the water. The tank seems overly bright. I have five crocea clams, and if anything- they seem to be losing some of there color, but doing well otherwise. (the clams are between 6-8" off bottom). I don't feed the tank- and the oldest clam is about 6months (~5"). All WQ parameters are in desirable range for clams. Any thoughts on the effectiveness of this set-up? And why the clams are fading to brown?

 

[Don Berry]

I'm not sure why the are browning out, but it is not the lighting. That would be ideal lighting for Crocea's. They do better underintense lighting. Mine does great under 2x250 DE's.

 

[mbbuna]

please post your test #'s

 

[FINFISH]

please post your test #'s

I recently added a calcium reactor (two weeks ago):

pH: 7.8
Alk: 10.0
Cal: 440-450

Before the reactor was installed:

pH: 7.9
Alk: 8-9
Cal: 400- 410

Total sys volume ~105gallons
Water change ~5-10%/week

 

[E-A-G-L-E-S]

Crocea's and Maxima's LOVE all the light you can throw at them, so it's not the light-IMO

ph is a little low !!

 

[FINFISH]

I'm not sure why the are browning out, but it is not the lighting. That would be ideal lighting for Crocea's. They do better underintense lighting. Mine does great under 2x250 DE's.

That's what I had in mind when I purchased these lamps.
Do you think it would be worthwhile to drop the halide fixture ~6" closer to the water surface? It has a shield, and I don't get much splash in such a deep tank. The T5's would have to go away until I could figure a way to drop them as well.
The confusing thing to me is the apparent new shell growth accompanied by the browning.
Additionally, I was concerned about therebeing too much light because the clams would start to close up one or two hours before the end of my photoperiod (we've had enough! ) and consequently, I reduced the daylight period by an equivalent amount (at the beginning) and now they stay fully extended all the way through.

 

[FINFISH]

Crocea's and Maxima's LOVE all the light you can throw at them, so it's not the light-IMO

ph is a little low !!

My pH has definitely always been on the low side (and I don't know why). I've read up on the topic quite a bit- and came to the conclusion that it would probably be ok, as long as I keep the other parameters on target.

 

[E-A-G-L-E-S]

that is true....my ph sits at 8.0 but alk and calc. and mag. are kept in check and it is fine

 

[mbbuna]

I recently added a calcium reactor (two weeks ago):

pH: 7.8
Alk: 10.0
Cal: 440-450

Before the reactor was installed:

pH: 7.9
Alk: 8-9
Cal: 400- 410

Total sys volume ~105gallons
Water change ~5-10%/week

can you please add Ammonia, nitrite , nitrate and Po4
and did the browning start after you shortened the lighting?

 

[FINFISH]

can you please add Ammonia, nitrite , nitrate and Po4
and did the browning start after you shortened the lighting?

TAN: 0
NO^2: 0
NO^3: 0-10ppm
PO^4: unknown, I don't have a kit for it.

I use an RO/DI for makeup (and salt water prep)- with conductivity generally less than 10mS

The largest Crocea I have came to me with a brown coloration (except for a fringe of blue eyes)- I've had it under these conditions for ~7months w/o any change.
The other four Croceas (that I purchased from Clams direct) came with very good color and have progessively become more like the first one. (I've had them for ~3 months).

 

[fishieness]

what is your salinity?
are you noticing any other fading in coloration between your other inhabitents?
you might want to try feeding some phyloplankton.

 

[FINFISH]

Salinity is 35ppt

Only other inhabs are hermits, snails, and a pygmy angel & five line (I think)wrasse- all are in good shape (and I haven't noticed any nipping at clams)
I don't have problems with nuisance algae.
I also keep a 15gal refugium with muchos caulerpa macro and a snowflake eel- healthy pop of amphipods

 

[mbbuna]

Fin the way everything looks (from what you've posted )your clams shouldn't be browning out. the only thing i can think of is that maby the bulbs are getting old or that your nitrates/phosphates are higher then your tests are leading you to believe. and what that can do is allow your zoox to grow faster then the clam can process them and there waste.i dont think that the clams are in any trouble , just not as colorful as you would like. try cutting back on feeding or anything that might lower your nitrates and phosphates.
hope this helps.

Chris

 

[FINFISH]

Thanks for your feedback. I'll order a PO^4 kit to look into that further.