Perhaps you’ve discovered an unknown, green/brown feathery, rapid growing algae called Bryopsis. This algae is often confused with Green Hair Algae and Caulerpa, and is misidentified by most local fish stores. It’s an algae that you can keep ripping out clumps of and it seems to grow back overnight. Bryopsis can appear unexpectedly and can take over a saltwater aquarium in a few of days. It usually attaches to Live Rock and is easy to remove, but the algae is fragile and may break into many small pieces. If manual removal is attempted, you must use a siphon to suck up any free floating Bryopsis to keep it from reattaching to the live rock.

If the uncontrollable algae you have sounds like Bryopsis, don’t worry. Thankfully there is an easy way to eliminate Bryopsis. Raising the magnesium in your aquarium to 1600-1700ppm seems to melt Bryopsis away. Kent Marine Tech-M is the only magnesium product that seems to work. Many hobbyists have tried other magnesium products with no success. There is no explanation for why this product works better than others.

How to Kill Bryopsis Algae

1. A large enough bottle of Kent Marine Tech-M to raise your saltwater aquarium’s magnesium to 1600-1700ppm. The typical 55-75 gallon aquarium will need a 128 oz treatment of Kent Tech-M.

2. A quality Magnesium Test Kit, like Elos or Salifert to measure the magnesium levels in your aquarium.

3. A Siphon and bucket to remove any free floating Bryopsis

Eliminate Bryopsis Instructions

1. Use your magnesium test kit to determine your aquarium’s magnesium level.

2. Read the instructions for Kent Marine Tech-M to determine how much will need to be dosed to raise your aquarium’s magnesium to 1600-1700ppm.

3. Over 2-3 days elevate the magnesium levels and test an hour after every dose. Magnesium can be raised safely 200-300ppm every day. If you happen to exceed 1700ppm, no ill effects have been reported up to 2000ppm. Remember to shake the bottle of Kent Marine Tech-M before use.

4. Once a magnesium level of 1600-1700ppm has been achieved, the Bryopsis should begin to melt away within a matter of hours.

5. Ready your gravel vacuum and a bucket and siphon out all the Bryopsis.

6. Replenish your lost saltwater with pre-mixed saltwater to maintain your aquarium’s water level and salinity.

7. Monitor for signs of any new Bryopsis growth and siphon as necessary. You also need to continue dosing Kent Marine Tech-M.

8. After the Bryopsis has been eliminated, you can allow your magnesium levels to naturally fall to normal levels. The optimum reef aquarium magnesium level is approximately 1350ppm.