Red algae on back glass

[cliftonsinclair]

OK I've got some brown diatoms that always appear on the back glass. Well now there is really deep red spots in it. Is that coraline or is that a bad algae? Tried to get a pic all you could see is the brown.

 

[cav]

sound like it could be cyno. What size is the tank? What flow do you have? Do you have anything pointed at the back glass? What are your nitrate/phosphate readings? Have you changed the light recently?

 

[cliftonsinclair]

20 gallon, Flow is the same as always nitrate is 15 and no I havent changed the lights but I do have my new T5 fixture coming thursday

 

[cav]

Flow is the same as always

What flow do you have and is it hitting the back glass?

 

[cliftonsinclair]

900 gph power head plus my HOB. It is not directly hitting the back glass but the current is getting to it.

 

[cav]

I had a similar problem in my 25 gallon and that was with 700 gph, I added another powerhead of 300 gph behind my rockwork and it helped loads, the added flow reduced my nitrates to 0. Have you tested your nitrates and phophates?

 

[cliftonsinclair]

yeah I tested my nitrates yesterday and they were at 15 and yeah I don't test for phosphates?

 

[cliftonsinclair]

I didn't know more flow could lower your nitrates

 

[cav]

I didn't know more flow could lower your nitrates

You need to test for phophates as they are good source of food for bad algae. More flow over the rock means less detrius build up, less dead spots and the rock becomes more effecient at converting nitrates to nitrogen

 

[cliftonsinclair]

Thanks, I guess I'll go get a smaller powerhead and aim it at the back