Not sure what to do.

To answer these questions there simply isn't enough info here.
Can you put up a list of your equipment and your feeding routine?
Lights

What skimmer
Refugium
GFO
Basically we need to know your nutrient import and export routine.
What stands out at me is your PO4.
Those API kits do not read low enough even if it says zero all tanks have some PO4.
If it is showing something on the card at all most likely it is way too high.

Also if not running a GFO reactor the first thing I would do tomorrow is buy one and some GFO.

 

I feed them twice daily not very heavy. My lights run actinic on at 10am daylights on at noon daylights off at 8 p.m actinic of at 9pm.

Skimmer. Coral ife super skimmer 65
Fuge esshoppes 75
Top fin 40 hob filter
Ocean pulse duo with two fluval sea 750 gph pumps
And a mean green killer (small version )
I don't run a reactor and don't plan to but I use phoszorb in my filter sock.

 

+1 for the peroxide treatment. If you can take the rocks out, make up a solution of, say, 10% peroxide to tank water (old tank water from a water change) and put your rocks in for 10-20 minutes or so. Pick off all the algae you can get your hands on, then dunk/rinse in another bucket of old tank water (to get the peroxide off), then put back in the tank.

Here's a thread with more detail: Peroxide saves my Tank! With pics to Prove It! - Disease & Pest Treatment - Nano-Reef.com Forums

I've done this treatment a couple times when I've had bad algae. It works pretty well, but you do have to revisit in a week or so and do the same thing again to get it all. Zoas and polyps deal with the peroxide pretty well, but if you've got sps, I'd be more careful and just pull the rocks out and spot treat the algae with a stronger peroxide mixture, then dunk to rinse, then back in the tank.

Also, good luck!!

 

we are talking about hydrogen peroxide correct?

 

Algae needs: Light and nutrients
Lights: Type, spectrum and age. Older lights lose their advertised spectrum over time. If the lights are old it may be time to get new lights. Go for a bluer spectrum... if you normally go for 10k.. pic a 20K
Usually the bigger culprit is the nutrients.
Nutrient export:
Skimmer. Is the skimmer producing decent skimmate? How often are you cleaning out the cup?
Normally with an average bio load people clean those out 2-3 times per week. If you're having an algae problem and it's pulling out gunk clean it more often. They perform better when clean... I mean clean the neck... not the whole skimmer.

Fuge:
You listed your type of refugium but that basically tells people you have a box with something growing in it. In order to help people help you they need to maybe have a pic so we can see what is in it or tell us how big is it, how much macro is in it. A pic is worth a thousand words.
Reactor:
Running GFO passively in a sock is not going to do much. If I had an algae problem I would immediately buy a reactor and the higher end GFO. Use the standard GFO after the algae problem is gone. Unless you have a big refugium with established macro. If you have a tiny ball of chaeto that needs to grow it's not going to help much until it gets to a certain size. Also the light in the fuge matters. 3500-6000K. The more powerful the better macro growth.

There's more than one way to skin a cat of course... heck I just read about a guy on RC using a Xenia refugium as his main nutrient export for 11 years.

Consider an algae scrubber. Easy to make and cheap.
I've run algae scrubbers before and if I had an algae problem in the display I would set up my old algae scrubber for sure. It will starve the algae in the display. Algae scrubbers require a good bit of research though. The main thing is to clean off some algae every week.

I am just touching on a few things here. You know your tank better than we do so just keep reading on the subject as there are a million threads on this.
Since there are several factors just try and hit the algae from all angles. If you just take rocks out and scrub them the algae will just come back if you don't cure the root cause.

 

Oftentimes,
What reads 0, is not actualluy zero. It may be low, but somethings going on. Apparently Inorganic Phos is not detectble by the test kits, or maybe it's the Organic Phos, not sure, but you have had some good advice already about how to try and help fix it.

 

Yep!

 

Well I am going to start dosing with vinegar and I am going to dip a couple rocks with peroxide.

I just have one question with the vinegar dosing. Do you maintain your dosage until you break down the tank or just until all the algae seems to be gone?

 

So, dosing vinegar works! I have been doing it for 3 days and i am already seeing a lot of dead and dying algae! Thanks much for the tip on carbon dosing!!!!!!;D

 

great to hear. keep us updated.