Can anyone help me find out why my chaeto will not grow. I have grew it well before using a Fluval Marine and Reef 2.0. After 6 months no growth I bought an 18W Waterproof LuxBird grow light off Amazon. Still no growth. I grow all other algae’s just fine. I’ve even put in a hamster ball and got it floating at the top of the fuge water level as close to the light as possible. I have also tried dosing iron for 3 week with no change. For the past 3 weeks I have continued dosing iron and also dosed Brightwell Chaetogro with no growth.