Description
API pH Down is a liquid treatment for freshwater aquariums that need to sit lower on the pH scale than the tap water will allow. It is the one to reach for if you keep soft, acidic water species such as discus, angelfish, neon and cardinal tetras, rasboras or apistogramma, and your tap supply comes out hard and alkaline. It is safe for fish and for live plants.
Aquarium pH does not stay where you put it. Fish waste and uneaten food push it around, topping up with tap water drags it back toward your supply, and alkaline substrate, shells or limestone decor nudge it upward. That is why API recommend testing weekly rather than assuming it has held.
The honest part matters. pH is very easy to overcorrect, and a fast swing is harder on fish than a steady reading they are not native to. Most community fish adapt well to a stable pH slightly off their ideal and cope far worse with a number that moves every few days. Add small amounts, wait, retest, and repeat only if you need to. A stable tank with healthy fish is usually best left alone.
- Lowers pH in freshwater aquariums to your target level
- Safe for fish and for live aquarium plants
- Use when setting up a new tank, during water changes or when correcting drift
- Suits soft water species kept in naturally hard tap water
- Available in a 118ml bottle
This is a freshwater product and is not for marine or reef aquariums. Test before and after every adjustment, and follow the dosing on the label. Compare it with the rest of our complete aquarium water care selection.