Testing Your Nitrate Test Kit
- Take 1000ml of water. Dissolve 6.5 grams of KNO3 in it.
- Take 1 gallon of water. Each ml of the above solution will add 1 ppm of NO3.
- Add 5 ml, test. Your test kit should show 5 ppm.
- Add 5 more ml, test. Your test kit should show 10 ppm
- Repeat through the range of your test kit.
- (Thanks Rex )
edit: split photo periods are no problem at all so I would forget that being a possible problem (done it for years here)
Plants can't use nitrates without phosphate though and as I posted low phosphate levels cause me algae issues.