Zero Nitrates?

[Raimond]

I have a 110Gal FOWLR tank that is over 3 years old.. Mostly small fish but one Dog Faced Puffer who is a messy eater. I have always had problems with nitrates. When I got the tank it was already over 2 years old and running with nitrates at 160.
The nitrates were high for along time, aggressive water changes would bring them down some (never below 80) but they would climb back up, mostly due to over feeding. I was new and wanted to keep everyone happy.
Last month I converted part of my sump into a refugium and added a couple of different macros and a cleanup crew to the main tank. Chaeto is the most prominent, I have a piece that is about the size of two fists. Slowly my nitrates have been coming down, for a week they were between 5 and 10 its hard to tell sometimes with the API kit. This morning they were at zero, I checked it again and sure enough zero. My other parameters are all zero.

My questions are..

It this possible to have zero nitrates with a med loaded tank?
Is this OK, the macros have to have something to eat and grow? Or is it that they are just doing a bang up job and have enough to consume?
My red nuance algae continues grow next to the refugium light but not in the main tank, I think part of it is that I switched to LEDs on the tank...
I want to add a yellow tang and a few more small fish to add color to the tank.

Ideas?
Thanks in advance!

 

[Krypt]

It is definitely possible to hit 0 nitrates on your test kit. What that is telling you is that your macro is doing its job efficiently. There are still nitrates in the water, however your macro is now using them as fast as they are produced giving you the 0 reading. As for the red algae, you could scrub it off and give your macro time to out compete it to make it go away for good, but it will take some time. All in all your refugium is doing what it is supposed to!

If you add a new fish, of course the load will change and it will take some time to go back down to 0 again while the macro grows. Sounds like you are in a good spot!

 

[Raimond]

Thanks krypt,

I just noticed my red nuance algae is getting small bubbles on it, what does this mean?

 

[austinsdad]

Red with bubbles. I'm thinking cyanobacteria.

So, you got a cleanup crew with a puffer?

Also, it's OK to feed once every other day.

 

[Raimond]

Austinsdad,
Thank you for the response,

I found this on About.com,
"Commonly referred to as "red slime" algae, the name cyanobacteria literally means "blue-green" algae. Despite the naming, only about half of these organisms are actually blue-green in color. Most forms found in saltwater are other colors, ranging from blackish green to blue-green, from orange-yellow to reddish-brown, and often appear deep purple to fully black in color. Starting out as small patches, it spreads out from there as a mat of sheeting covering."

I see what you are alluding to, my puffer does not bother the snails or hermits at all. Maybe because he is well fed. Many have questioned the same issue, to me and Chompers its not an issue.

 

[melosu58]

We have a good article on cyano in our articles section. What size CUC dou you have. I would always suggest every other day feeding.

 

[Raimond]

I have about a 100 small snails of different types and maybe 20 hermit crabs most are small and 4 are rather large ones.

I just did a small water change as I brushed the algae off the rocks as best I could while sucking it out with a gravel vacuum hose.

 

[Krypt]

I have about a 100 small snails of different types and maybe 20 hermit crabs most are small and 4 are rather large ones.

I just did a small water change as I brushed the algae off the rocks as best I could while sucking it out with a gravel vacuum hose.

That's about all you can do really. Just keep on it and as the macro grows, hopefully you'll see no more.