Brown acros - what steps to take?

[kilnakorr]

Hi sps experts.

I got two acros a couple of months ago.
They have quite brown since I got them.
I know the issue can be many different things, so was wondering if I could get some ideas on what to try first.
Some info:

90gl tank (+30-ish gl sump)
Salinity: 1.025
Ph: 8.15-8.25
Alk: 7.5-8.0
Ca: 420
Mg: 1350
NO3: 11.7
PO4: 0.02

Dosing AF 3 part, and AF nitraphos minus (AF NoPox).
I recently started the 'nopox' dosing and so far NO3 has dropped 2ppm over the last two weeks - started slowly.
PAR is 300 and 180 as they are not placed together.

So, what would you recommend I should try first?
Lower NO3?
Increase light?
Increase flow?
Other?

A picture (the shortcake behind it has decent colors):

 

[jcdeng]

browning usually is too little light and/or too much nutrient, but I believe its more on the lights.

 

[kilnakorr]

browning usually is too little light and/or too much nutrient, but I believe its more on the lights.

So your recommendations is increase light?

 

[WestonNanos]

Looks like you have some nice color on the coral to the right, are you sure its not just the coral itself?

 

[Doctorgori]

I’ve had sticks go brown for a lil while at 1st, but wait for input from more competent stickheads, let’s see what they say….
anyway, IME they color up eventually…
Turn up the blues for now and give ‘em some pop while. u wait

 

[jcdeng]

So your recommendations is increase light?

higher par, and also spectrum matters, I don't know what lights you are using currently, but if LEDs, brand does matter.

 

[ScottB]

Some acros are just going to do that -- especially wild ones. Aquacultured less so.

180 PAR is a little on the low side and can certainly be a cause.

IMO, your nutrients are not too high, in fact your PO4 could be too low. But talk about your fish feeding habits. It is okay to have ultra-low nutrients if you are feeding 3-8 times a day. Otherwise, a .02 with a +- error measure of .02 could be too close to zero.

Here is what 10/.1 for nutrient and 250-550 PAR looks like in my 120.

 

[kilnakorr]

Looks like you have some nice color on the coral to the right, are you sure its not just the coral itself?

Not sure of anything.
Just wondering, as the issue is with both corals placed in opposite side of the tank.

I don't know what lights you are using currently, but if LEDs, brand does matter.

Radion XR15 G4 pro.

180 PAR is a little on the low side and can certainly be a cause.

IMO, your nutrients are not too high, in fact your PO4 could be too low. But talk about your fish feeding habits. It is okay to have ultra-low nutrients if you are feeding 3-8 times a day. Otherwise, a .02 with a +- error measure of .02 could be too close to zero.

The one receiving 300 PAR has the least color/more brown.
I usually don't run my PO4 that low, but seems the AF nitraphos minus has a decent impact on PO4 which I didn't see when using NoPox.
Was running at 0.05-0.08 until a week ago.

 

[jcdeng]

radions are good enough, maybe just increase the power gradually