Acro problems


Community Member
Review score
+0 /0 /-0
View Badges
Feb 1, 2020
Reaction score
Review score
+0 /0 /-0
So I've been dealing with some sort of issue with my corals, particularly acropora, over the course of the last 4-5 months. It's been a steady degrade, both visually and in element consumption. Before whatever happened, things were really looking good all around.

My tank is a WaterBox 7225 that's been up for 483 days.

  • Nyos 160 skimmer
  • Clearwater Turf Scrubber 200
  • Filter socks
  • Two Tunze 6105s
  • Two Gyre 350s (opposite sides of tank)
  • 4 Ecotech Marine G5 XR15s Pros
    • 7am to 6:30pm
      • 4 hours peak starts at 9:30am, ends at 1:30pm
      • followed by lower intensity, less white
  • 2 60" ReefBrite LumiLight Pros (actinic)
    • Turn on at 9:30am
    • Turn off at 3:30pm
  • Two part (Sodium Bicarb, Calcium Chloride)
  • Manual magnesium
Additives (over the course of the year):
  • AquaForrest Pro Bio S
    • Daily 8 drops earlier in 2021, but stopped sometime in summer I think
  • Flatworm Stop
    • not for pest | stopped dosing after 3-4 months starting in April
  • Eco-Balance
    • actually stopped dosing at end of July, but started again with daily doses starting in November
  • Red Sea Iodine (Trace Colors)
    • once a week, 2ml
  • Red Sea Iron (Trace Colors)
    • once a week, 40ml <<<These happened in August and had direct impact on nutrients that month because of ATS and nuisance bubble algae, so I stopped dosing.
  • Brightwell Potassion
    • inconsistent dosing, but did do a heavier correction after an ICP test in July, and a few smaller ones between then and another ICP in October. The results still showed potassium on the lower side of acceptable.
  • Witchhazel
    • This was dosed because I have speculated this problem is rooted in bacteria causing tissue necrosis, possible stemming from low nutrients.
      • 3 daily doses
        • Nov. 14: 60ml
        • Nov. 15-16: 30ml
    • This definitely ticked off many of the acro frags, causing minstrel filament flare, and probably triggering some heavier STN, but I can only really attribute 1 death so far. This is why I stopped at 3 days, instead of going for the 5-7 days as prescribed from my source (Andre's writeup for Moonshiners method)
    • Overall, this did seem help something, as observed by the alk stability after a week of recovery.

Alk - Tested with Hanna Colorimeter, mostly tested in morning, but occasionally test more than once a day

I pointed out the contents of the red box because I don't think the perceived jump in alkalinity is real. I started a new bottle of Hanna alk reagent and previously noted that the bottle I finished has a stark difference when starting it.

Calcium - Tested with Red Sea Titration

Magnesium - Tested with AquaForrest Magnesium Titration

Nutrients - Nitrate with Nyos, Phosphate with Hanna ULR Colorimeter

Note the drop for both nutrients in August, which I believe was caused by iron dosing and its impact on my ATS

ICP Tests
July 30th:
October 31st:

Despite some values out of range, I don't think water quality wrt elements is a problem.

I have some progression pictures that portray most acropora in my tank. At this point(Dec. 2nd), I've lost 4-6 acro frags due to complete tissue necrosis. Please note the dates - the first compilation ends on today, whereas the others are back from November. So there is still some crap hanging on, or the problem just look longer to manifest on certain coral.



So I'm really trying to understand what is the root cause here.​

I am still a very new reefer - I'm two years in. I don't have all the answers or experience.

My best interpretation for timeline is:
  1. Dosing of iron in August boosted my ATS into overdrive and bottomed out my nitrates
  2. I was not vigilant on fixing this because I was following general advice - of you got algae, you got nutrients - and yup, after iron was dosed, bubble algae got worse
  3. My perceived lack of nutrients for effectively 3 months weakened corals, making them susceptible to bacteria
  4. I dosed witchhazel, which I feel wasn't a bad choice
  5. I am now trying to raise nutrients back to levels before issues started in September, and am seeing
    1. some positive things (faint color returning to some acros)
    2. some stagnant things (brown and polyp-extension-less corals remain so)
    3. some negative things (corals that seemed to tough it out are having a delayed reaction)
Other thoughts/counter points:
  • Problems popped up after stopping Flatworm Stop - pure speculation - but I know the dosing of this and AF Pro Bio S started to allow me to keep acros around 6months of tank maturity (after lots of problems earlier in tank lifespan)
  • Maybe my nutrients have been abundant, but am getting false low readings because of the bubble algae and the extra nutrients is actually causing zooxanthellae to brown out and get ticked off
I'm having a tough time figuring out if I'm out of the weeds and just seeing acros having their delayed reactions, or if something is still awry. I did get a small batch of new corals (3 acros) and their PE is good! But I also know there could be a delayed onset here as well.

Please share your interpretations!
Last edited:


10K Club member
Review score
+0 /0 /-0
View Badges
Jun 25, 2013
Reaction score
Review score
+0 /0 /-0
Boulder, CO
I would recommend that you change your paradigm on what you are calling nutrients. First, separate the term nutrient into energy and building blocks.

Energy comes from the lights - it can sometimes come from other areas, but let's stop here for the moment. Have you used a PAR meter at all? xr15s are not strong lights, but they might be fine.

Building blocks are N and P, mostly, but also some aminos. First, your corals don't need amino supplements - they get sold as gold but tanks that don't add them don't suffer. Second, residual values on a test kit are fools gold - you want available nitrogen in ammonia/ammonium from your fish and all forms of phosphate/phosphorous also from feeding your fish.

In short, the basic recommendations of maybe more/better spectrum with some T5s might be a good idea. Also, keep feeding your fish and if you skimp, then feed them more - feeding fish is paramount and a paradigm of heavy import and heavy export is a good one.

Do you change water in good quantity? If not, then start. Water changes are the cheapest and most effective way to have good change. 200g box of IO which makes about 176 gallons is less than $40 and can do wonders.

Iron is needed by macro to grow. No surprise that bubble algae took off once you dosed leading me to believe that you were iron deficient which also leads me to believe that water might not be changed enough since water changes supply iron. Your turf algae will appreciate the iron too. You didn't ask about this but Emerald Crabs from Reeftopia destroy the stuff for me - real Florida Keys crabs, not just generic Emeralds from who knows where. They live about three years, or so, so you have to to replace them over time.

I don't think that the witchhazel hurt, but it probably did not do anything either. This is PURE speculation, so probably not worth much.


Active Member
Review score
+1 /0 /-0
View Badges
Mar 20, 2020
Reaction score
Review score
+1 /0 /-0
Agree with poster above on all points but one question.

How quickly did you stop flatworm stop as I’ve read that it’s like drugs for corals that you can’t just abruptly stop and needs to slowly decrease dosage until you stop.


Active Member
Review score
+0 /0 /-0
View Badges
Dec 27, 2016
Reaction score
Review score
+0 /0 /-0
I don't like that tin in the icp & looking at the pics i would have called high Po4 issue but if we consider the Hanna is telling the truth then i think maybe your border line on too little light.
Or maybe its the tin doing it - i don't know.
Your tank is something close to a 160G ? with 4 x xr15's ?
My 160G i have 4 x XR30 (AB set at 100)

Tin is going down so maybe things will improve on their own.
Iodine where it is on the latest icp is also not a smart place to have it.
Top Shelf Aquatics


Active Member
Review score
+0 /0 /-0
View Badges
Sep 20, 2020
Reaction score
Review score
+0 /0 /-0
Tin contamination, typically secondary to pvc pipe or flexible tubing. Organotins are added to prevent biofouling of plumbing by killing anything that comes in contact with them. Some of this leaches out into the water and you get coral death. Cuprisorb is supposed to aid in removal.


Have you ever torn down a tank over an issue you couldn't seem to beat?

  • Yes! I have. (Tell us about what issue you faced in the thread.)

    Votes: 115 24.6%
  • No. Thankfully, I haven't.

    Votes: 243 52.0%
  • Nope, but it almost happened. (Share your experience in the thread.)

    Votes: 34 7.3%
  • Not yet, but I'm almost there. (Tell us what you're dealing with.)

    Votes: 40 8.6%
  • If you reef long enough, this will eventually happen to you.

    Votes: 30 6.4%
  • Other

    Votes: 5 1.1%

New Posts