Double Points April - Purchase this item and get 
To maintain and grow healthy corals, the correct balance of calcium and carbonates is essential, as are low levels of phosphate and nitrate.
This kit provides highly accurate testing for each of these critical parameters:
Calcium
KH
Phosphate
Nitrate
Unique, transparent dome allows clear view of contents.
Kit includes computer-calibrated and laminated color cards, 4 glass test tubes and holding tray.
Also contains complete, step-by-step instruction booklet, including information on how to correct unsafe water conditions.
Compact to store.
