If the pH is too low then the cause may be a too low alkalinity and/or insufficient aeration. A low pH can be corrected by improving aeration and by increasing the alkalinity to NSW (Natural seawater) value or upto approx 25% above NSW levels. The Salifert pH test kit is sufficiently accurate to monitor pH fluctuations of approx 0.2 pH units. Our KH + pH Buffer allows fast and efficient correction of alkalinity. Approx. 50 tests per kit. Range pH 7.4 - 8.6. The pH value can have a major impact on the growth of corals and calcareous algae and on many biological processes. The pH should not be allowed to fluctuate more than approx. 0.3 units during 24 hours and should preferably be kept between 8.0 and 8.2.