I have noticed a purple sponge-like mass growing at the top of my mixed reef tank. In the last 6 months it seems to have accelerated in size and a second growth has appeared in recent weeks.
Should I be concerned that it’s taking nutrients from my corals? If so, what are the best ways to remove it? Or any advice on what to do to stop it growing?
The two LED lights mounted above the tank are in a 8 hour cycle, mostly in the blue range for the latter part of day.
My current corals include a couple of torches and hammers, a bubble coral, GSPs, Galaxia, Zoas and Pallys, and a couple of mushrooms.
Live stock includes a foxface, melanurus wrasse, engineer goby, Midas blenny, royal gramma and a couple of clowns… plus a CUC of snails, conch, hermits and a cucumber.
It’s an 55 gallon tank (Reefer 250) with built-in fuge that adds another 30 gallons plus ATO. It’s been up and running for about 3.5 years.
Water parameters:
- PH 8.0
- Phosphate .1
- Nitrate 0
- Ammonia 0
- Calcium 511
- Temp 78
- Salinity 1.025
Thank you for any suggestions

Should I be concerned that it’s taking nutrients from my corals? If so, what are the best ways to remove it? Or any advice on what to do to stop it growing?
The two LED lights mounted above the tank are in a 8 hour cycle, mostly in the blue range for the latter part of day.
My current corals include a couple of torches and hammers, a bubble coral, GSPs, Galaxia, Zoas and Pallys, and a couple of mushrooms.
Live stock includes a foxface, melanurus wrasse, engineer goby, Midas blenny, royal gramma and a couple of clowns… plus a CUC of snails, conch, hermits and a cucumber.
It’s an 55 gallon tank (Reefer 250) with built-in fuge that adds another 30 gallons plus ATO. It’s been up and running for about 3.5 years.
Water parameters:
- PH 8.0
- Phosphate .1
- Nitrate 0
- Ammonia 0
- Calcium 511
- Temp 78
- Salinity 1.025
Thank you for any suggestions

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