AMERICAN MARINE - PINPOINT PH CALIBRATION FLUID American Marine Sale! from 150 /per Options American Marine Pinpoint pH 4 Calibration Fluid American Marine Pinpoint pH 7 Calibration Fluid American Marine Pinpoint pH 10 Calibration Fluid Qty. Add to Cart This item is currently on backorder but you can still purchase it now and we'll ship as soon as more become available. Pinpoint pH Calibration Fluid Available in 4.0, 7.0 and 10.0 packets. For use with most aquarium pH probes.