I have been running my 20-gallon nano reef for about 18 months. Things have been very stable and looking great for about 9 months. No algae, happy fish (3) and zoas (3), and stable water parameters. I have been doing ~20% water changes every two weeks. About 3 weeks ago, I started to notice a very dark (almost black) algae on the tops of my rocks, and some green algae started to form on my sand (glass has been clean). About 4 days ago, I noticed that one of my Zoas was not fully opening. 3 days ago, my goby wasn't visible, even during feedings. I usually feed a very small amount of pellets 3 times a week, and I target feed the zoas twice a week with 1/16 tsp of reef roids mixed in tank water using a long dropper. I did a water change and tested my water, and got the following parameters (all with Hanna digital tester):
Phosphate: 0.18ppm
Nitrate: 35.5
Nitrite: 2ppb
Ammonia: 0.19 (Hanna measures total ammonia) **EDIT** - I noticed on the Hanna app it shows the NH3 is 0.07ppm
Salinity: 1.026
Temperature: 78 degrees.
I do use a small bag of Chemi-pure elite in the sump of my tank. I change it about every 3 months. I also have ceramic bio material in one section of the sump.
Today, all three zoas were barely open. I found a dead red knee hermit crab, and after searching the cracks of the rocks with a flashlight (through the glass), I believe my goby has died (I have no way of getting him where he is located because all of my rocks are epoxied together, and he is in a small crack).
I did another ~15% water change tonight. Since everything has been stable for so long, I'm not sure what changed. I am cutting back to feeding twice a week, hoping to reduce the Nitrates. Other than that, I'm not sure where to start to stabilize my tank. I am open to any suggestions others may have.
Phosphate: 0.18ppm
Nitrate: 35.5
Nitrite: 2ppb
Ammonia: 0.19 (Hanna measures total ammonia) **EDIT** - I noticed on the Hanna app it shows the NH3 is 0.07ppm
Salinity: 1.026
Temperature: 78 degrees.
I do use a small bag of Chemi-pure elite in the sump of my tank. I change it about every 3 months. I also have ceramic bio material in one section of the sump.
Today, all three zoas were barely open. I found a dead red knee hermit crab, and after searching the cracks of the rocks with a flashlight (through the glass), I believe my goby has died (I have no way of getting him where he is located because all of my rocks are epoxied together, and he is in a small crack).
I did another ~15% water change tonight. Since everything has been stable for so long, I'm not sure what changed. I am cutting back to feeding twice a week, hoping to reduce the Nitrates. Other than that, I'm not sure where to start to stabilize my tank. I am open to any suggestions others may have.
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