Acropora so brittle - help!

[Donovan Joannes]

When I remove a 7" diameter bubblegum digitata yesterday, I discovered that it was so brittle, it almost crumbled when I broke off the main stem.

I don't do water changes (purposely to save cost, I am not a rich reefer). I manually dose strontium, iron, trace elements and iodide to keep the tank happy. Am i missing something?

I also dose kalk on dripper (continuosly, keeping alk at 8, calcium slightly over 400) and magnesium weekly (above 1380ppm).

Nutrients is at good level, SG at 1.026. Using RODi for top off (auto). All corals seems happy and growing. Any help is very much appreciated.

 

[Donovan Joannes]

This was the digitata I am talking about. Everything looks fine, but the brittleness was very surprising. Some acros are showing same issue (faster it grows, the more brittle it gets)

 

[Dsnakes]

Are the broken parts new or old growth? I believe that is a calcium deficiency. It's growing quick, but not solid.

Tank looks great by the way!

 

[Donovan Joannes]

Are the broken parts new or old growth? I believe that is a calcium deficiency. It's growing quick, but not solid.

Tank looks great by the way!

Thanks for replying. This acro was grown from frags, so the whole branches were brittle. My calcium never go below 400ppm as I am dripping kalk round the clock. Another thing is most of my acro grows a thinner corallites. I believe I have strong flow (sand moving around).

 

[Flippers4pups]

Looks like your numbers are good. Thin branches with good tissue, color and polyp extension are usually indicative of low flow. Higher flow with SPS usually have thicker branches.

Not everyone will have this condition and will vary between types of SPS.

 

[Donovan Joannes]

Looks like your numbers are good. Thin branches with good tissue, color and polyp extension are usually indicative of low flow. Higher flow with SPS usually have thicker branches.

Not everyone will have this condition and will vary between types of SPS.

I have 2 jebao rw8 at 100%, alternating mode. Facing up as further downwards will blow some acros directly and ripped off my blastos. Will laminar flow help?. Alternating creates rolling waves but not hitting corals all the time.

 

[Flippers4pups]

I run a laminar alternative flow in my tank. Most of my SPS have thick branches. Digitata's and birdnest...... etc.

 

[Donovan Joannes]

I run a laminar alternative flow in my tank. Most of my SPS have thick branches. Digitata's and birdnest...... etc.

Okay. I will try laminar flow for a month or two.

 

[cobra2326]

What are your phosphate levels? There are a few recent studies that show phosphate can increase growth but also increase brittleness (supposedly by "poisoning" the structure because it substitutes for normal calcification ions).