How is this possible?

[NikeLV]

I got the API reefmaster test kit and just tested nitrates and phosphates.. both read 0.0 ppm mg/L! I have lots of algae growing in my tank, brown algae and green hair algae! they come back one after the other. is there something wrong with the test kits? is there some OTHER cause for my algae growth? My LFS also tested my water and read 0.0 ppm nitrates/ phosphates.

[Reefing Madness]

I got the API reefmaster test kit and just tested nitrates and phosphates.. both read 0.0 ppm mg/L! I have lots of algae growing in my tank, brown algae and green hair algae! they come back one after the other. is there something wrong with the test kits? is there some OTHER cause for my algae growth? My LFS also tested my water and read 0.0 ppm nitrates/ phosphates.

Brown Algae with a new tank is usually Diatoms. the Hair Algae may not be that, but the harder to get rid of one called Bryopsis.
Diatoms:

The silicates the Brown Algae requires can enter your tank through several avenues: Commercial sea salts, tap water used for top offs and make up and the substrate you may have on the bottom of your tank.
If you did absolutely nothing to your tank, the Brown Algae would eventually consume the silicates present and die of starvation. Since you can't do absolutely nothing to your tank, the source of the silicates must be identified and eliminated, in order to get rid of the present brown algae bloom and prevent future outbreaks.

• Check the source of any builders sand, play sand or other substrate materials in your tank which did not come from the ocean. There is a possibility that they may contain silicates which are leaching into your tank water.
• Use only RO or RO/DI water whether you purchase an RO/DI unit or purchase RO/DI water from a commercial source.
• Check to see if your commercial sea salts contain high levels of nitrates. If the salt mixture contains unacceptable nitrates, consider changing mixtures

Bryopsis:

Nuisance Hair Algae - Bryopsis plumosa and Derbesia - Reef Health

[NikeLV]

Brown Algae with a new tank is usually Diatoms. the Hair Algae may not be that, but the harder to get rid of one called Bryopsis.
Diatoms:

The silicates the Brown Algae requires can enter your tank through several avenues: Commercial sea salts, tap water used for top offs and make up and the substrate you may have on the bottom of your tank.
If you did absolutely nothing to your tank, the Brown Algae would eventually consume the silicates present and die of starvation. Since you can't do absolutely nothing to your tank, the source of the silicates must be identified and eliminated, in order to get rid of the present brown algae bloom and prevent future outbreaks.

• Check the source of any builders sand, play sand or other substrate materials in your tank which did not come from the ocean. There is a possibility that they may contain silicates which are leaching into your tank water.
• Use only RO or RO/DI water whether you purchase an RO/DI unit or purchase RO/DI water from a commercial source.
• Check to see if your commercial sea salts contain high levels of nitrates. If the salt mixture contains unacceptable nitrates, consider changing mixtures

Bryopsis:

Nuisance Hair Algae - Bryopsis plumosa and Derbesia - Reef Health

Oh wow, thank you . Do you happen to know if Instant Ocean Reef Crystals contain nitrates or phosphates? and miracle mud? I drain the filthy water from my protein skimmer but I don't scrub it, could that be a problem of algae? Hopefully my new RO/DI system, miracle mud, and chemipure elite helps reduce, or even demolish, the algae in my reef

[Reefing Madness]

Reef Crystals is pretty good stuff. You don't have to clean out your skimmer body but maybe once every 6 months. The stuff your using should take care of the issue, along with your Sea Hare. I don't know that much about Miracle Mud.

[NikeLV]

do you yourself use a DSB in your refugium?

[Reefing Madness]

do you yourself use a DSB in your refugium?

I don't utilize a sump.