Diatoms or what?


New member
So I have this rust coloured algae everywhere. I suction it out and clean the glass and it's back within an hour. Where the tank receives the most light there are tons of bubbles. Also in the brightest sections it gets strands that break off. I have googled my heart out and can't figure out if it's diatoms or dinos.

Parameters are:
Ammonia - 0
Nitrites - 0
Nitrates - 10
Mag - 1300
Cal - 380
Alk - 8.3
Sal - 1.024
Temp - 78

Tank is 3 months old. Fish and corals are happy and healthy.






New member
It's not cyano. It's rust coloured. Not in a sheet with bubbles. There are millions of small bubbles stuck to the surface of it but only when lights on.


New member
Diatoms. Just part of new tank uglies. Battling some of it myself but it goes away with water changes and keeping params in line. My skimmer actually pulls out a good amount of it.

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Martin Kuhn

New member
+1 for NOT Cyanos, most likely diatoms

Attention: a tank looking like this has a high risk for beeing infected with dinoflagellates and or cyanos later on

- improve your water flow !! (additional flow pumps, change direction of flow, maybe remove or re-arrange life rock)
- install a cleaning crew for your sand or AT LEAST clean your sand by your self right now
- get rid of the silicates that must be in your tank
a) Adsorbers for silicate or also PO4 adsorbers work to reduce the stuff already in your tank
b) make future fresh water used silcate free ! (much cheaper and less problems than if you handle silicates within your tank)

wishing you success


In Memoriam
The strands that break off are cyano.The dust looking brown stuff on the glass are indeed diatoms.


New member
I've started skimming wet and it seems to be abating. I do a 40g water change every weekend. There is quite a bit of flow in the tank (I think). Anymore and the hammers are miserable. So just wait and see? I was tempted to do the three day lights out but if it won't help....