Green algae on sand?

[Ab129]

Had what I believed to be diatom outbreak a month or two ago.
Added CUC and my water has cleared significantly but I still have this stuff on the surface of much of my sandbed (about 1 1/2 inches deep).
Phosphate tested 0, Nitrates 0, radion xr15s on a preset “reef tank” schedule.
It looks brownish in color but when I take all the blue light out it looks green.
That is how I set the lights to take the pic below.
I added a bag of phosbond to my sump today to see if that helps (lfs recommendation)
What do I need to do to get rid of this stuff?
I do a weekly 15% water change.
Thank you for any suggestions!

Photo will not upload for some reason (very frustrating)
will try again later

[AlSimmons]

Cyanobacteria? This does come in all kinds of colors.

[lapin]

When we get the picture we can help you ID this. How old is the tank? If you have 0 phosphate, i'm not sure why they said to use phosbond. Your post has 2 nitrate numbers. Were they 10ppm at one time?

[Uncle99]

What is the length and intensity of the "reef tank" schedule.
This automation varies wildly, I seen one with a 12/12 photoperiod at 100%, which of course, turned the reef into a green mess....

If you turn off the light for 3 days, does the algae start to withdraw?

Algae needs two things, nutrients and light, deprive it of these things and it DIES.
I trust you use RODI water with a TDS less than 5 right.

[Ab129]

Nitrates were at 10 but have been 0 for weeks, I just never changed the number in my sig.
lights are on for 10 hours at 25% intensity. I have 2 BTA and three frags so I can’t turn the lights off for three days.
RODI at 0 TDS.
I’ve taken about 10 pictures and cannot seem to upload 1 successfully but I’ll keep trying.
The phosbond didn’t really make sense to me either but for 8 bucks I didn’t see the harm in trying.

[Uncle99]

Turning out lights for three days will not hurt your BTA or frags?
Nitrate at 10ppm is a bit, on the higher end when you gave few corals.
Shoot for 0 ppm until you gave a moderate coral load, then 3-5ppm.
You can consider less feeding or carbon dosing, this will bring down the nitrate.
Yup, the pic would help, in some cases, the algae can be normal as a tank natures.

[lapin]

Originally Posted by Ab129

I’ve taken about 10 pictures and cannot seem to upload 1 successfully but I’ll keep trying.

For pictures i have to jump thru hoops. First i make them about around 100kb with photoshop, as suggested in the drop down. I have slow internet so it helps anyway. I hit "go advanced" when that box pops up I chose my picture and hit the upload. Then it tells me to login again. Im all ready logged in. So I login again using that screen. Then I have to close that screen to make it work. I then go back and hit "go advanced" and manage attachments again. It will let me upload a picture. Then to post I have to login again. It is so weird.

[Ab129]

Pics should be there now I hope

[stingythingy45]

How old is this tank?
Looks to be cyano.
Make sure your skimmer is running to full capacity.
More flow will help and make sure you are not overfeeding.
A few nassarius snails will help.

[Ab129]

First fish added 6 months ago. Lights on since February.
Have a CUC in place with some nassarius snails. Could always add, especially since my wrasse was kind enough to thin the herd of snails lol!
What is “full capacity “ for skimmer?

[lapin]

Could be cyano. If so you can turn off the lights for a day. If a lot of it disappears thats usually cyano. A black out will get rid of it. When the lights come back on it will regrow. The key is to have something out compete it. If you keep siphoning it out and turn the lights to a lower intensity with more blue it will help. Something in your tank will eventually take up those avail nutrients and the cyano should disappear as the tank matures.

[Uncle99]

You will need to experiment to find the root cause, if it's algae, you need to take away its food, that is, light, and your Nitrate, too High at 10ppm, as you have no coral load.
Lower feedings and/or carbon Dose. Maybe try LC, like agent green, bug this is only a temp fix until you find ou whether it's the light, the nutrients, or IMO, both...

[Ab129]

Nitrates are not 10, they have been 0 for weeks.
I was probably feeding a little too much. I had just introduced a new fish and was having aggression issues so I was giving a little extra to minimize the urge to compete for food.
Have started feeding a little less and tried to vacuum up some of this stuff when I did my WC Sunday
How long can I turn lights off with BRAs and frags?

[Uncle99]

sorry, I was mistaken about your nitrate count.
2-3 days dark is fine for both, the ocean does not have light every day, see what effect on the problem.
Vacuum, water change, and make sure their is adequate flow, dead spots will accumulate algae as well, just keep up the good work, your numbers appear fine, she should settle out if your input water is TDS <5, and the changes weekly for now.
Keep in mind that for a medium coral load, they do better when nitrate is 2-5ppm and phosphate .02-.04 ( your not there yet, but when you do, zero will starve them)

There's also no issue with putting all the numbers on point for NSW now and working towards stabilization of these, this is critical to great success...

[Ab129]

Thanks. I have a gyre for flow and the problem doesn’t seem confined to one or two remote areas so I don’t think flow is a problem.
Lights out for two days and we’ll see what happens.