Should I clean or not?

My tank is about 2 months old. I am getting serious brown diatom algae on my rock... I cleaned it twice but of course within a day its back. Should I just let it build up thick, or should I keep cleaning it off periodically? I am using ro/di water and running a 216 T5 fixture. I also thought about cutting the light down.. or should I just let it go full?

 

it may be diatoms that will be self limiting once the silicates are used up although you are at the outer edge of time that they should be going away. I might cut back a little on the lights although if it's diatoms, that won't make a difference. Bump for your question!

 

It seems like they just have to run their course. They'll go away on their own. As ofk said, the silicates will eventually get used up. Not sure if there is anything that will spurred up the process.

 

Hi cleaned it off last night and just took pic now

 

it does look like diatoms with a little bit of cyano - I'd let them run their course, I know it's yucky looking and I'm sure tempting to want to clean it off but you're working against yourself by doing that.....

 

I have some pulsing xenia, a mushroom and some tiny green star polyps. Will it ruin them if I leave it to grow too much?

 

My nitrates are very low like 10-15.. would it help at all to do a 20% water change? I am close to due for one soon anyway

 

Pretty much 0-.10 phosphates

 

those are hardy corals that shouldn't be bothered by the diatoms. If you're due for a water change, I'd go for it. 10-15 is not super low on nitrates imo

 

Thanks. I did the water change yesterday. I left the lights off today. I do get some natural light in the room.. but not direct