Algae ID and help

[Bsilb]

A few weeks ago I started to notice this green algae starting to grow on the rocks. It has since progressively gotten worse and worse. The tank is a 20g about 15lbs of dry rock and 1.5” live sand bed. It’s been running for about 4 mouths. Everything seems to be doing really well, 2 small fish lots of zoas some montipora and various snails and crabs. Also a couple shrimp. 
temp- 78-78.5

cal-410-430

alk- 8-9dkh

no2- 3-5ppm 

ph-8

thats all I test for. 
looking in algae a problem solvers guide I think it’s Cladophora? But I’m not 100% sure. 
I know I should be testing phosphates and just order a kit. (Don’t have it yet)

I’ve been doing 10-12% water changes weekly since I noticed the algae bloom. I also added chemi-pure elite about a week ago. 6.5oz. 
 

im hoping some of y’all could help me with what I can do to help the problem. I have read people talking about the rip and clean. I’m trying to avoid that. 
 

Thanks, Brett
 

[sadie]

Could you post a FTS and with the white lights on?  I can't really tell what I'm looking at.  Are the pictures upside down?

[Bsilb]

22 hours ago, sadie said:

Could you post a FTS and with the white lights on?  I can't really tell what I'm looking at.  Are the pictures upside down?

Lol. yeah looks to me they are upside down. posted them from my phone, dont know what happened there. 

Yes, ill take a couple better photos with the whites on later. Thanks for the reply 

[Bsilb]

Here is a couple photos with better lighting. I hope the upload doesn’t kill the quality. 
 

Any help would be great. Thanks!

[Bsilb]

What the heck?! I don’t know why they are upside down. They aren’t in my phone and when I added the files they were right side up. Lol. Hopefully someone can do a handstand and help me out 

[Bsilb]

Also. This is my light cycle 

[seabass]

I'm not sure of a proper ID.  Does your urchin appear to eat it?

 

I feel that I've had that before.  If it's the same thing that I had, It's especially hard to get rid of.  Is it only on the one rock, or throughout the tank?

[Bsilb]

The urchin isn’t eating it that I can tell. It’s a newer addition hoping that it would. It’s growing only on the rock and also on the back glass where I can’t get the scraper very easily. 
 

I have hand picked it when it gets long enough to grab. Between that and the chemi pure elite along with feeding a lot less. It appears to have slowed its growth. 
 

at this point I’m just going to keep the feeding down and keep up with weekly water changes. My next step if I don’t notice it get better will be turning the lights off for a few days? Think that may help?

[seabass]

A short blackout won't get rid of it.  Light deprivation that's enough to kill it would likely be enough to kill your corals too.

 

I might be half tempted to dip the rock in a strong algaecide solution (such as API AlgaeFix or Vibrant).  It might be difficult to control with just herbivores and manual removal.