Dust Algae?

[danbryans]

Was wondering if anybody could help identify this algae on the walls of my tank. At first glance you would see rust colored patch which cannot be rubbed off by hand. Used an old credit card to scrape it off. And it has a dust like appearance. Could this be GDA? But it always starts off with a rust color and not green. Has anybody encountered this same type?

Tank parameters
EI dosing
NO3 10ppm weekly
PO4 2ppm weekly
CSM+b 10ml (1.5tbs dilluted in 500ml)
CO2 about 30ppm (CO2 drop checker)
3.2wpg for 10hrs
35gals

Need help guys!

[FishFan]

How long has your tank been set-up? You should be having brown algae common with new set-ups where the cycling is not complete.

[danbryans]

This set-up is already 7months old. Brown diatom algae can easilly be removed even by rubbing with your finger's right? The rust colored algae i have only comes off when scrubed with a hard material.

[barmby]

I think it is spotted algae if you need to use credit card to scrap it

[danbryans]

Haven't really experience GDA so I don't know if it easilly rubs off or do you have to resort to using hard material's to scrape it off?

It could be some form of spot algae. If that's the case then maybe I'll up my PO4 dose and see if it can control it.

Thanks for your input barmby.

[barmby]

Green dust algae can be easily shaken off by touching the surface of the glass. There is another method to rid of green dust.

[StanChung]

I think it is spotted algae if you need to use credit card to scrap it

Any plastic like EZ link card or phone top up card also can.