Finding nitrates

[Myka]

In almost every case, you will get 0 nitrate long before you get 0 phosphate, so I don't see that being an issue. Your phosphorus to nitrate ratio makes sense.

Originally Posted by Proteus

Never really tested against another test kit. Just against nsw.

NSW is natural seawater. I don't hink you have any of that in Devon. I think you mean ASW; artificial seawater?

The hobby-grade test kits we use suck in the grand scheme of water testing ability of the human race. I've found lots of test kits that wander with age, even well inside the expiry. It's worth a double-checking.