CarbonVS – Nitrate remover.
Target: 0,5 – 2,5 ppm nitrate
Lower nitrate by increasing daily dose with 20% steps until target or maximum dose is reached. Reduce daily dose when water get blurred or nitrate is lower than 0,5ppm.
Dosing min/max: 0,5 – 5ml / 100l
Start dosing: 0,5g / 100l per day
Available package: 250ml – 500ml – 1000ml – 5000ml – 10Liter

"How to lower nitrate?
The way to reduce nitrate is to use a Carbon source.
Known carbon sources include Vodka, vinegar, sugar, citric acid, honey, dextrose, but also bio-pellets is a carbon source
In DSR I opted for the approach with vinegar but was not content, later i extended it with sugar (the Carbon V/S mix). I have tested with different ratios until i found an optimal one . I also customised a dosing table for this Carbon V/S mix.
The condition to be able to reduce nitrate using a carbon source, is that there must be some Phosphate present. Preferably to be kept at level 0,03-0,08ppm. It sounds very contradictory, but at lower levels (0,0<0,02ppm) dosing Phosphate will help to reduce nitrate to lower levels. I have experience this a few time myself, and others who followed up on my advice also experienced this.
The dosing of a Carbon source, especially vinegar/sugar can encourage the growth of sponges. I therefore i dose nitrate to stabilize my nitrate at a desired level. Keep nitrate at levels between 0,5-2,5ppm
When dosing carbon watch out for stress signals: milky water,  fish breathing heavily, slime on the corals, rocks and windows.  Half the dose in steps when this happens."

Glenn Fong, DSR Reefing