Algae problem

[Terryc]

My tanks been running for about 2 years now with no problems until now. I made a huge mistake of adding corals from a friends tank with dipping them.
Started to see what looked like diatom on my sand bed and thought it would go over time. A couple of days later it got darker and I started to see bubble coming from the sand that looked like snot. After research I realised I had dinoflaggate. So I started the stages that I had researched to remove this.
A 3 day black out.
Raising my ph with kalkwasser
Increased the flow
Added chemi pure elite
I already run phosban in a reactor
After 3 days I turned my actinic lights on and all the algae was gone. I kept just my blue lights on or about a week and nothing has come back.
My problem now is that iv got what looks like dust all over my rock and sand and can seem to clear it. Iv brushed the rocks off, siphoned the sand and performed massive water changes and it doesn't seem to be helping. any ideas of what to do would be appreciated.

 

[Animal-Chin]

when people say brown dust it usually means diatoms. If you blow water at it with a turkey baster does it just blow off? If it does you've got diatoms and they are consuming silicates in your tank. They go away naturally. I'd guess that by doing alot of sand syphoning you've stirred up a bunch of silicate into the water colomn that's feeding them. Try leaving the sand alone for a while.

Now if they don't just blow off its something else...

 

[Terryc]

Yeah they do brush off but come back the next day. Hopefully its just diatom then. Il keep doing water changes and leave the sand alone to see how it goes. Thanks for the reply

 

[hackteck]

yea sounds like diatoms to me they will burn out after a week or two most likely