What is this weird algae?

[Zoajohn]

This weird brown algae is growing over the rocks in my tank, stunting SPS encrusting. It doesn’t seem to be producing air bubbles on its own, and when siphoned comes off in spheres. It’s mainly in high light but can be found throughout my 13.5g tank. I’ve scrubbed with a brush a few times and it just comes back. In one pic you can see it around some of my sps, in another you can see it on a plug next to a millepora. How do I get rid of this?

 

[Bret Brinkmann]

Hard to tell from the pics but looks like dinos. If it looks like snot and gets worse throughout the day but gets better over night, then it's dinos. Usually happens when you bottom out nutrients with high lighting.

Get a good nitrate and phosphate test kit if you don't have one yet. Red Sea makes a good nitrate kit. Hanna LR phosphate or ULR phosphorus testers are generally the preferred testers.

Let me know if that is what it is and I can post how I beat them in my tank.

 

[Zoajohn]

Hard to tell from the pics but looks like dinos. If it looks like snot and gets worse throughout the day but gets better over night, then it's dinos. Usually happens when you bottom out nutrients with high lighting.

Get a good nitrate and phosphate test kit if you don't have one yet. Red Sea makes a good nitrate kit. Hanna LR phosphate or ULR phosphorus testers are generally the preferred testers.

Let me know if that is what it is and I can post how I beat them in my tank.

It is probably Dino’s. I had them a few weeks back, super dark brown and snotty. I beat them (I thought) with a black out and reduced lighting intensity. Now I just have this pillow type stuff over my rocks in high light. I think I’m going to try another blackout and get a UV filter. Know of any small ones?

 

[Bret Brinkmann]

They will keep coming back unless you manage your nutrients more. Blackouts work because it slows their need for nutrients. Once the lights come back on, the rate of nutrient use increases again, eventually they bottom out, then the bloom is triggered again.

Most people report their corals do better with some nutrients in the water too. Think of dinos as a sign that you are starving your corals. Phosphates will need to be about 0.1 ppm and nitrates at least 1 ppm.

UVs are good for getting some dino strands back down to a manageable level but it is not the cure. Here is the sizing info I performed for mcarroll's dino sticky thread in this forum.

...

UV Watts needed: 1 Watt or more for every 3 gallons. Example; a 100 gallon tank would need a 33W UV or more. 1 Watt for every 2 gallons would work faster, a 50W UV for a 100 gallon tank. There is no maximum for Wattage.

Flow Rate needed: Minimum of you tank volume (NOT actual water volume but tank volume) per hour. Maximum of 12 times your tank volume per hour. So a 100 gallon tank would need 100 gph to 1200 gph.

Again you want display tank volume not water volume. And only display tank need be used for calculations. The UV should draw from the display not the refugium. It's easier to just send the return line back to the display.