Question about water parameters for acropora

[Lapras]

Hi all,
I still consider myself relatively "newer" at this hobby, and was wondering some insights/thoughts on my current water parameters for my acros.

Alk: 9.5
Ca: 495
Mg: 1400
Nitrites: 0
Nitrates: 15 ppm
PO4: 0.12 ppm
Sg: 1.026
Temp: 79F

Two MP40 in Reefer 525

Water Changes every week, I usually empty the sump, so about 25%

Currently running some GFO to lower PO4.

Question: Is polyp extension a reliable indicator of acropora health?

Many of the acros have polyp extension, and a couple frags are encrusting on my LR. A couple others have polyp extension, but don't seem to be growing. This is over a 6 month or longer period. See pictures for captions.

Thank you all for your time.

 

[Fudsey]

What are you using for lights? It may be that your light isn't strong enough???

 

[vetteguy53081]

Lights and water flow play a vital key as does water quality.
Lights should be 60% blue and 40% white ramping whites down throughout the day. Water flow- med- high without blasting the daylights out of the acro and feedings 2-3 times per week suspended with water flow down to practically nothing

 

[Lapras]

Thanks for your response. I am using 3 x AI Hydra26.

Settings (BRS AB+ for Ai Hydra26)
UV: 118%
V: 101%
RB: 83%
B: 65%
G: 6%
R: 5%
CW: 19%

I don't feed the acros much, maybe once a week with ReefRoids; how long do you leave the water flow off while feeding?

 

[vetteguy53081]

Thanks for your response. I am using 3 x AI Hydra26.

Settings (BRS AB+ for Ai Hydra26)
UV: 118%
V: 101%
RB: 83%
B: 65%
G: 6%
R: 5%
CW: 19%

I don't feed the acros much, maybe once a week with ReefRoids; how long do you leave the water flow off while feeding?

I leave off for 15 minutes. I would do feedings 3X per week. Reduce white lighting a bit also

 

[Lapras]

Thank you. Do you also feed after the lights go out or during? What do you use?

 

[vetteguy53081]

About 20 mins before lights out and I feed Reef roids, coral frenzy and Reef chili

 

[Hitman]

Be careful with feeding reef roids a little goes a long ways and that could be causing your high PO4. I use a extra spoon for Salifert regents test kit and use 2 spoon fulls in a cup of tank water once a week and feed about 20 minutes before lights out. I do this every Saturday night just to stay on a easy day to remember.

 

[FLReefer]

Thanks for your response. I am using 3 x AI Hydra26.

Settings (BRS AB+ for Ai Hydra26)
UV: 118%
V: 101%
RB: 83%
B: 65%
G: 6%
R: 5%
CW: 19%

I don't feed the acros much, maybe once a week with ReefRoids; how long do you leave the water flow off while feeding?

When switching to this setting on your lights, did you use acclimatation mode? If so, what percentage?

 

[Lapras]

When switching to this setting on your lights, did you use acclimatation mode? If so, what percentage?

I used the setting, but lowered the percentages by about 20%.

 

[FLReefer]

I used the setting, but lowered the percentages by about 20%.

Thanks. Looking up that program now.

 

[PatW]

From what I read, your nutrients are a bit high.

Generally, I see nitrates recommended as anywhere between 1 ppm and 10 ppm. I run just above 1 ppm.

I see phosphates recommended as less than .03 ppm but greater than zero.

I have read of people running near zero on both phosphates and nitrates. They get around this by lavish feeding.

For low nutrient systems, you want the ALK at around 8 . You want your ALK to be as constant as possible.

For most acro, you want high flow and hopefully variable flow. You also want intense lighting with a considerable amount of the blue and violet spectrums because they are what drives photosynthesis.

For indicators of health, you want polyp extension, growth and color. You seem to be doing pretty well. Some of my SPS corals grow like weeds and others don’t. I would not worry. Just experiment and find frags that work in your system. I have read that some frags will sit and sit and sit and then decide to color up and grow.