We were away for just over 2 weeks over christmas, a pet minder was feeding the fish and since coming back our jewel tank has this weird brown stuff growing on the glass and heater. We cleaned the tank just before we went away. On the day we got back I scrubbed it off (its easier to get rid of than green algae), and now exactly one week later it is back. Does anyone know what it could be? If I took a photo it would just look dirty! All my levels in my tank are good, with pH now around 7, no ammonia, nitrites, nitrates etc. Fish are all well, although one was bullied badly and died a few days ago (unrelated to this I am sure, a new pair formed and they picked on this guy). Thanks.

We were away for just over 2 weeks over christmas, a pet minder was feeding the fish and since coming back our jewel tank has this weird brown stuff growing on the glass and heater. We cleaned the tank just before we went away. On the day we got back I scrubbed it off (its easier to get rid of than green algae), and now exactly one week later it is back. Does anyone know what it could be? If I took a photo it would just look dirty! All my levels in my tank are good, with pH now around 7, no ammonia, nitrites, nitrates etc. Fish are all well, although one was bullied badly and died a few days ago (unrelated to this I am sure, a new pair formed and they picked on this guy). Thanks.

my ottos fixed that but at least it's easy to clean off. It usually appears in newish tanks but it can grow in low light levels so maybe while you were away, it was building up due to no tank lights being on?

We were away for just over 2 weeks over christmas, a pet minder was feeding the fish and since coming back our jewel tank has this weird brown stuff growing on the glass and heater. We cleaned the tank just before we went away. On the day we got back I scrubbed it off (its easier to get rid of than green algae), and now exactly one week later it is back. Does anyone know what it could be? If I took a photo it would just look dirty! All my levels in my tank are good, with pH now around 7, no ammonia, nitrites, nitrates etc. Fish are all well, although one was bullied badly and died a few days ago (unrelated to this I am sure, a new pair formed and they picked on this guy). Thanks.

Would be easier if you posted a photo, could be diatoms.....

Could be silicates that have caused the breakout. What lighting are you using? Usually - green algae = too much light, brown algae = too little light.

I've cleaned it off already sorry. The lights were not on whilst we were away. The tank has been going in its current spot for well over a year so not new. Do you think its a type of algae? My pH has risen slightly over the last month but its now ideal for my fish. What are diatoms? We have pretty good lights actually GLO T5 HO ones. Thanks.

I've cleaned it off already sorry. The lights were not on whilst we were away. The tank has been going in its current spot for well over a year so not new. Do you think its a type of algae? My pH has risen slightly over the last month but its now ideal for my fish. What are diatoms? We have pretty good lights actually GLO T5 HO ones. Thanks.

Sweet, you had diatoms. No light for the holiday has caused it.

Thanks. Must've been some cloudy days whilst we were away!