Test Kit Reads 0 Phosphate & Nitrate

[Collinw24]

So I have had a tank set up for a few years now, and one thing I've never tested is phosphate. I just haven't felt the need to since the tank never had bad algae and I've always used RO/DI water.

Just recently, I decided to add a refugium. It's just a 10 gallon tank that I drilled that sits next to the sump, and branches off my return line. I smashed up a couple pieces of live rock and added a big chunk of chaeto. For lighting it's one of those 23w CFL bulbs in a homedepot clipon light. The refugium has been set up for about a month now, and I've noticed that the chaeto has started to lose it's color and die.

I've decided lately that I want to get this tank in full swing, so I started ordering a bunch of the things that I never really had but probably needed. One of which included a Salifert phosphate and nitrate test. I tested the water and to my surprise both test read 0. I retested both, just to make sure I did everything right. Same result.

So this brings me to a couple questions.

1. Is it possible and OK to have 0 nutrients?
2. Are the Salifert test good? I was planning on having a buddy check the water too, but just haven't gotten around to it.

 

[twilliard]

Some systems can be just fine in the ULN state. They are managed much differently than a nutrient tank.
If your tank is doing fine I wouldn't worry about it and keep doing what your doing.
Now if you are seeing a tank that is just not up to par then yes no3 and po4 should be available.

 

[Nano sapiens]

One thing to keep in mind is that if you have life in your tank, you will always have some nitrate and phosphate. However, the lower limits of the test kits may not be able to measure it.

If you have corals, and they are healthy/colorful without constant external feeding, then you have sufficient NO3 and PO4 in the water.