I have had a macro algae (Chaeto) and it was doing great until just recently. I have a small 2 gallon tank for my macro which isn't even half the size of it. I had about a half inch of live and in there as well. I regularly added sodium bicarbonate and nitrogen to keep the algae alive. It was doing great but suddenly deflated and isn't growing. I checked levels of nitrate, nitrite, alkalinity, and ph. I did salinity and temp many times as well and everything was in check. Filter and heater were operational as well. I recently did a 100% water changed as well and did not add sand to the new tank to try and limit unwanted algae growth. Still it is not thriving as it was. There are no other organisms in the tank either. I am a little sad and definitely confused. If anyone has any info or advice of any other tests I can do please let me know thanks!