http://www.customaquatic.com/customaquatic/index.asp
di-HI93728 Nitrate Digital Colorimeter, 0.0 - 3.0 mg-L. 2 Year Warranty.? $139.99 (NT$4900)
di-HI93720 Calcium Hardness Colorimeter 0.0-2.70 mg-l Hanna Digital Instrument 2 year warranty? $159.99 (NT$5600)
di-MKMR100-ATC Refractometer with ATC (automatic temperature compensation) for accurate salinity measurements. Milwaulkee. $89.99 SalePrice: $65 (NT$2300)
有NO3, Ca, 鹽度...電子水質量測器, 看起來很高檔, 價錢也很高檔, 除了鹽度計外, 有人用過其他產品嗎?

之前有向 Andyhu 兄借NO3-N的電子比色儀

請問效果好嗎?
聽說還需要加藥劑, 但是我在網站上沒看到單賣藥劑, 也不知道價錢如何...