Aqua One pH Up Liquid for Fish Ponds 250ml
Increases pH for small ponds and fish tanks
Use if your pH is too low (too acidic) use 5 - 10 mL for every 100 litres of water.
Retest after 24 hours
Ideally, pH is something that you want to alter slowly, over a few days if possible, so that your fish do not become stressed.