Acro Help

theblobfishman · Oct 17, 2025

Hi, I've been struggling to keep acros in my tank and would like some advice. I don't have a Phosphate or Calcium checkers yet but I have ordered them and will update later but here are the rest of my parameters. Acros just strip completely overnight which makes me think its a water chemistry issue.

Its a 35 Gal AIO setup
Tank has been up for at least 6 months
Alk is 10.5 dkh
Magnesium is 1380
PH is 8.05
Salinity is 1.025
Temp is 81 degrees F
Nitrates are at 0.0
Light is provided by 2 Red Sea LED 50's set at 30% Blue 50% White
I also have been using Red Sea's NOPOX
I have a kalkwasser setup for this tank I turned it off because I was wondering if the increase of PH was causing them to strip/bleach

Any help would be appreciated

smitten with ocean life · Oct 18, 2025

@Troylee

Troylee · Oct 18, 2025

theblobfishman said:
Hi, I've been struggling to keep acros in my tank and would like some advice. I don't have a Phosphate or Calcium checkers yet but I have ordered them and will update later but here are the rest of my parameters. Acros just strip completely overnight which makes me think its a water chemistry issue.

Its a 35 Gal AIO setup

Tank has been up for at least 6 months

Alk is 10.5 dkh

Magnesium is 1380

PH is 8.05

Salinity is 1.025

Temp is 81 degrees F

Nitrates are at 0.0

Light is provided by 2 Red Sea LED 50's set at 30% Blue 50% White

I also have been using Red Sea's NOPOX

I have a kalkwasser setup for this tank I turned it off because I was wondering if the increase of PH was causing them to strip/bleach

Any help would be appreciated

Most likely a nutrient issue.. with alk that high you need higher nitrate and phosphate.. it appears they are starving from your numbers.. I’d stop the nopox also as that’s why your nitrates are zero and it’s most likely feeding a pathogenic bacteria and causing you problems..

billyocean · Oct 18, 2025

Troylee said:
Most likely a nutrient issue.. with alk that high you need higher nitrate and phosphate.. it appears they are starving from your numbers.. I’d stop the nopox also as that’s why your nitrates are zero and it’s most likely feeding a pathogenic bacteria and causing you problems..

Spot on.

81⁰ temp is about to have to show a passport to get into the danger zone as well. Any reason its so high? If you can run it fairly steady 77 give or take a degree that may help also. Being that they strip within 24 hours makes me ask what youre dipping with and or if you've done an icp to identify any potential contaminants in thr tank. 6 months could be enough time to have acros and it could be not enough. All depends on the rock maturity i.e. dry rock....live rock.....Ocean live rock start? What acros are you trying? But yeah...nutrients are bottomed so no need for ghr NoPox

reefpanda · Oct 18, 2025

To add most of the SPS you're buying comes from lower KH systems. Putting them into your system immediately gives them a 2 dKH shock hence RTN

Mr. Mojo Rising · Oct 18, 2025

How is the flow in your tank?
Why do you keep you blue's so low? I would get the blue's up to 75% at least IMO

theblobfishman · Oct 18, 2025

Troylee said:
Most likely a nutrient issue.. with alk that high you need higher nitrate and phosphate.. it appears they are starving from your numbers.. I’d stop the nopox also as that’s why your nitrates are zero and it’s most likely feeding a pathogenic bacteria and causing you problems..

Ok, I’ll stop dosing nopox for now. Is there a range of nitrate/phosphate that I should be aiming for when trying acros?

theblobfishman · Oct 18, 2025

billyocean said:
Spot on.

81⁰ temp is about to have to show a passport to get into the danger zone as well. Any reason its so high? If you can run it fairly steady 77 give or take a degree that may help also. Being that they strip within 24 hours makes me ask what youre dipping with and or if you've done an icp to identify any potential contaminants in thr tank. 6 months could be enough time to have acros and it could be not enough. All depends on the rock maturity i.e. dry rock....live rock.....Ocean live rock start? What acros are you trying? But yeah...nutrients are bottomed so no need for ghr NoPox

I’ll go ahead and drop the temp to 77, the rock used is a combination of live and dry rock but mostly live rock.

theblobfishman · Oct 18, 2025

Mr. Mojo Rising said:
How is the flow in your tank?
Why do you keep you blue's so low? I would get the blue's up to 75% at least IMO

Where I am placing the acros there is pretty good flow so I dont think that is the issue. I’ll go ahead and bump up the blues to 75 percent.

Mr. Mojo Rising · Oct 18, 2025

theblobfishman said:
Where I am placing the acros there is pretty good flow so I dont think that is the issue. I’ll go ahead and bump up the blues to 75 percent.

slowly, small bumps over time till you get there so the corals can acclimate

lbacha · Oct 18, 2025

I would be careful stopping nopox cold turkey as you may get a massive nutrient jump which can cause a lot of other issues.

A couple things I saw
DKH is pretty high, you can run it that high as it can promote sps growth but you have to know what you are doing. I would shoot for around 8 dkh

Temp is high, 81 is the top of the range you want your tank to get to. If that is your target then there is a good chance to are going over that number which can cause issues

Salinity is low, you want to target 35 ppm or around 1.0264 specific gravity. 1.025 use to be the target for fish only tanks as they are fine with a bit lower salinity but that means your only 33 ppm. This is more important as it means all of your other trace elements are lower as well.

0 nitrates can cause any number of issues, odds are your phosphates are 0 as well due to the nopox. Coral need food and a large percentage of that comes from nitrates and phosphates

Calcium is not that big of a deal if you are using Kalk then it may be a bit high shine your alk is but that shouldn’t be causing issues other than calcification on your equipment

I typically don’t worry about slow acclimation of SPS if my tank is similar to where I got the coral. Most coral farms keep dkh lower, salinity higher and temps lower so that may be why the SPS you add RTN so quick. You will need to do a slow acclimation to make sure you don’t shock the coral since your parameters are high/low in some cases.

Having said all that SPS can live and even thrive in your parameters but you will need to acclimate them to them. This is why I recommend adjusting your parameters to match closer to where you are getting the coral from.

theblobfishman · Oct 18, 2025

lbacha said:
I would be careful stopping nopox cold turkey as you may get a massive nutrient jump which can cause a lot of other issues.

A couple things I saw
DKH is pretty high, you can run it that high as it can promote sps growth but you have to know what you are doing. I would shoot for around 8 dkh

Temp is high, 81 is the top of the range you want your tank to get to. If that is your target then there is a good chance to are going over that number which can cause issues

Salinity is low, you want to target 35 ppm or around 1.0264 specific gravity. 1.025 use to be the target for fish only tanks as they are fine with a bit lower salinity but that means your only 33 ppm. This is more important as it means all of your other trace elements are lower as well.

0 nitrates can cause any number of issues, odds are your phosphates are 0 as well due to the nopox. Coral need food and a large percentage of that comes from nitrates and phosphates

Calcium is not that big of a deal if you are using Kalk then it may be a bit high shine your alk is but that shouldn’t be causing issues other than calcification on your equipment

I typically don’t worry about slow acclimation of SPS if my tank is similar to where I got the coral. Most coral farms keep dkh lower, salinity higher and temps lower so that may be why the SPS you add RTN so quick. You will need to do a slow acclimation to make sure you don’t shock the coral since your parameters are high/low in some cases.

Having said all that SPS can live and even thrive in your parameters but you will need to acclimate them to them. This is why I recommend adjusting your parameters to match closer to where you are getting the coral from.

Ok, slowly overtime I’ll reduce the alk to 8dkh, bump salinity to 1.026, lower my temp to 77, and do slower drip acclimation for new acros