Care
Alkalinity without the swings
The number matters less than whether it moves.
Pick a value between 7.5 and 9 and defend it. A tank held at 7.8 for a year grows corals; a tank oscillating between 7.8 and 9.2 grows frustration.
Test at the same time of day. Alkalinity falls through the photoperiod and rises overnight, so a morning reading and an evening reading are two different questions.
Dose continuously rather than in one daily slug. A doser running twelve times a day costs the same as one running once and removes the swing entirely.
Common objections
Terms used here
- Alkalinity (KH)How much carbonate the water carries, and the single number stony corals care most about.
- SPSSmall-polyp stony corals — the demanding, fast-growing, colour-shifting end of the hobby.