Do nems/BTAs need SOME phosphates to do well?

[Oceansize]

I've had a BTA doing well in my tank for several months, close to a year in fact.

Lately it has been acting unhappy, moving around the tank quite a bit, shrinking in size dramatically. Acting like a nem that is getting too much light basically, but I have reduced my intensity to 25% in response and the nem is still in decline.

Ironically, my water has never been cleaner. I have never, EVER had my phosphates down to zero until recently (0.00 on the Hanna checker. Not 0.03. Not 0.02. Not 0.01. But actually 0.00, triple-checked.)

Meanwhile my nitrates have remained stable as a table at 5ppm (Salifert & API)

So basically I'm wondering if phosphates at absolute zero could be a reason for the nem's decline. Does anyone else have experience with this? Just wondering if zero phosphates are a credible explanation before moving on to other theories...

P.S. Yes I do feed the nem Mysis and squid from time to time. Eating response is decent, but not as good as it used to be.

Ammonia & nitrite= 0 ppm
Nitrate= 5 ppm
Phosphate= 0.00 ppm
Alk= 10 dKh
Calcium= 510 ppm
Magnesium= 1350 ppm
Salinity= 1.024
Temp= 79-80
2x Kessil 360s

 

[DeniseAndy]

I am not sure it is too much light. Is it moving to the shade? If not, it may want more light. If it was T5s or MH I would suggest changing bulbs, but with a Kessil, not sure as I do not use LEDs much.

I would say that all my BTAs have liked my "dirtier" water tanks. Then again, I rarely have to feed them due to this and they host clowns that feed them nicely.

Not sure that was any help, but I would maybe turn lights up, not down. Feed broadcast a bit more.

 

[bairdimusprime]

I am not sure it is too much light. Is it moving to the shade? If not, it may want more light. If it was T5s or MH I would suggest changing bulbs, but with a Kessil, not sure as I do not use LEDs much.

I would say that all my BTAs have liked my "dirtier" water tanks. Then again, I rarely have to feed them due to this and they host clowns that feed them nicely.

Not sure that was any help, but I would maybe turn lights up, not down. Feed broadcast a bit more.

spot on couldnt have said it better

 

[Oceansize]

I am not sure it is too much light. Is it moving to the shade? If not, it may want more light. If it was T5s or MH I would suggest changing bulbs, but with a Kessil, not sure as I do not use LEDs much.

I would say that all my BTAs have liked my "dirtier" water tanks. Then again, I rarely have to feed them due to this and they host clowns that feed them nicely.

Not sure that was any help, but I would maybe turn lights up, not down. Feed broadcast a bit more.

That occurred to me, however the action I took that prompted all of this was that I turned my lights UP a little. Within 48 hours of turning them up a little, he started moving after having been in the same place for months. So I figured "well I guess I turned my lights up too much" and knocked them down to 25%, with the intent of not turning them back up until he returned to normal behavior, but the odd behavior has continued. And yes he appears to be trying to get into more shade. So I did a full round of testing and the result that surprised me was phosphates at zero. All other parameters are the same as when the nem was thriving.

 

[DeniseAndy]

I know with LEDs I have seen friends make the mistake of turning them up too fast. Maybe turn up, but only a tiny bit at a time and over a couple weeks apart. Definitely get some food in the column for it. How old is the system? Sounds like well over a year. Having any algae issues? What corals are in there? Any clowns or shrimp?

 

[malira]

Has your flow changed? I have a bta and a Sherman rose nem, the bta hasn't moved in 2 years, no matter what. I've changed from led to t5s, added 2 rw8s, return pump that tripled my flow and nothing. I added the srbta about 6 months ago with no changes in anything and it won't sit still. It found a home for 3 weeks and then on the move again.

I know lights and flow can make them move but sometimes there is just no pleasing them.

 

[Oceansize]

I know with LEDs I have seen friends make the mistake of turning them up too fast. Maybe turn up, but only a tiny bit at a time and over a couple weeks apart. Definitely get some food in the column for it. How old is the system? Sounds like well over a year. Having any algae issues? What corals are in there? Any clowns or shrimp?

The tank completed it's cycle just over a year ago. Algae control has never been better (I'm assuming it's due to 0.00 phosphates). I have LPS and SPS, the LPS are doing great, the SPS could be better but fortunately they are improving (I recently went from manually dosing Alk & calcium to using a Calcium reactor because I wasn't being consistent enough with my Alk supplementation, and that is why the SPS are improving). I have two cleaner shrimp, which I keep away from the nem when I'm feeding the nem. I have a maroon clown which is hosted to the nem in question.

Flow has not changed.

I know there are many possible explanations that involve flow, lighting, etc. But my first objective is to eliminate zero phosphates as a possible explanation before moving on to other explanations. I'm curious if anyone can definitively eliminate that as a possible reason.

 

[malira]

I have 0 phosphates and have had as much as .04 ppm. No difference for me.

 

[zoomonster]

That's a tough one and not sure what the issue is. The bunch of RBTA's I have now started under MH/T5 and in a day I switched to Kessil's and I only did a fairly short acclimation. I think my A36oWE's are at 75% power and 76% (was lower but tweaking) color right now and if anything many of the RBTA's moved a little closer to the lights. Like someone else mentioned mine seldom if ever move. All my nem's are on one end of the tank now and getting hit by 2 kessils.

It can't hurt to get your phosphate and nitrate up a bit though. While it may or may not help, everything, SPS included, should do better. Just start feeding more overall and give the BTA some squirts of mysis occasionally.