I have diatoms in a Nano that was set up several months back. It’s a 10L low tech with a 7W LED and small internal filter. Temperature is about 25c at the moment. Photo period is about 8-9 hours. Substrate is just Unipac aquarium sand and I’m using rainwater exclusively. I do about a 50% water change once a week. Flow in the tank is good and plants are growing well on TNC all in one. Any ideas why I’m still getting this? I’m not bothered having to clean hardware etc but it means taking Anubias etc out of the tank to clean them which isn’t good. I don’t have any inmates at the moment as it’s only 10L. Would a couple of shrimp help, if so what type? Anything else I can do that I’m not doing at the moment? TIA.