AquaVascular KH Down 250ml — Carbonate Hardness Reducer

Lower stubbornly high KH without shock to livestock

AquaVascular KH Down is a controlled acidifier for aquarists dealing with excessively hard carbonate water. High KH — common in Kerala’s borewell water and much of coastal India — makes it difficult to hold stable low-pH environments needed for planted tanks with soft-water species like discus, apistogramma, and many tetras. KH Down safely reduces carbonate hardness in measured, gradual steps.

When you’d use this

• Planted tanks running CO2 injection where high KH is preventing you from reaching a stable pH of 6.5–6.8
• Soft-water community tanks stocked with tetras, rasboras, gouramis, or apistogramma that need KH under 4 dKH for breeding condition
• Discus and altum angelfish tanks that require very low KH to thrive and colour up properly
• Blackwater biotope setups replicating Amazon or Southeast Asian conditions where KH is naturally near zero
• Shrimp tanks with Caridina species (Crystal Red, Taiwan Bee) that need soft, low-mineral water

How to use it safely

Test your KH before starting. Add KH Down gradually — never more than 2 dKH reduction per day. Rapid KH swings destabilise pH and stress livestock. Dose near the filter outflow so the product mixes evenly through the water column. Retest KH after 4 hours and again the next day before deciding whether to dose again.

Important warnings

• Do not use in tanks with high-KH-demanding species — most African cichlids, brackish tanks, and marine setups need high KH.
• Never dose blindly. Always measure KH before and after. A KH test kit is essential — we stock AquaVascular’s own KH test kit for exactly this purpose.
• Pair with a pH monitor during initial adjustment, especially in tanks with fish already stocked. If pH drops below your target, stop dosing immediately.
• Not for use in tanks with active CO2 dosing without close pH monitoring — combined KH-lowering and CO2 injection can cause dangerous pH crashes.

What’s in the bottle

• 1 × AquaVascular KH Down, 250ml

Manufactured in India by AquaVascular. Backwater Aquatics is an authorised AquaVascular dealer.