APT SKY PLUS

2HR Aquarist APT SKY PLUS – GH & KH Remineralizer

APT SKY PLUS is a highly concentrated remineralizer for freshwater aquariums running on RO or soft water. It raises general hardness (GH) without touching NPK values — and unlike its sibling APT SKY, it also moderately raises KH and buffers pH, giving fish and snails that prefer harder, more alkaline water the stability they need.

What Makes APT SKY PLUS Different

Standard remineralization only addresses GH, which works well for soft-water species but leaves KH and pH unstable for livestock that wants more buffering. APT SKY PLUS raises KH to roughly 2 dKH and buffers pH to 7.2–7.6 alongside GH, which suits guppies, mollies, snails, and hard-water-preferring plants far better than a GH-only formula.

It's roughly three times more concentrated than standard remineralizers, so a small, precise dose covers a meaningful volume of water rather than requiring large scoops of powder per water change.

Key Benefits

• Raises GH, moderately raises KH, and buffers pH to 7.2–7.6 in one product
• No effect on NPK values, so it won't interfere with plant fertilization
• Highly concentrated powder formula
• Well suited to livebearers, snails, and hard-water plant species
• Safe for shrimp, fish, and plants at recommended doses

Composition

• Calcium (Ca): 16.6%
• Magnesium (Mg): 3.5%
• Iron (Fe): 0.05%
• Boron (B): 5 mg/L
• Copper (Cu): 1 mg/L
• Manganese (Mn): 13 mg/L
• Molybdenum (Mo): 0.01 mg/L
• Zinc (Zn): 8 mg/L
• Seaweed extract: Less than 1%
• Form: Powder

Who Should Use APT SKY PLUS

• Tanks running RO or soft tap water that need GH, KH, and pH raised together
• Livebearers such as guppies and mollies, which prefer harder, more buffered water
• Snails, which need adequate KH and calcium for healthy shell growth
• Hard-water-preferring plant species

If your livestock is soft-water species — tetras, rare soft-water plants, or shrimp that don't need extra KH — the plain APT SKY is the better fit, since it raises GH only and leaves KH and pH untouched.

Dosing Instructions

• 3.5 g (5 ml) per 60 litres raises GH by roughly 2.5 dGH, adding approximately 12 ppm calcium and 3.5 ppm magnesium
• Standard starting dose with RO water: 15 ml (10.5 g) per 60 litres
• During water changes, dose based on the volume of water actually replaced, not the total tank volume

Expert Tip

If you're keeping a mixed tank — say, guppies alongside plants that prefer softer water — test both GH and KH before committing to APT SKY PLUS over the standard APT SKY. The KH buffering is the deciding factor: it stabilizes pH nicely for livebearers and snails, but can push water chemistry further than soft-water plants are comfortable with.

Frequently Asked Questions

Does APT SKY PLUS affect KH and pH?

Yes. Unlike APT SKY, it moderately raises KH to roughly 2 dKH and buffers pH to 7.2–7.6, alongside raising GH.

Is APT SKY PLUS safe for shrimp?

Yes, it's formulated to be safe for shrimp, fish, and plants at the recommended dose.

What's the difference between APT SKY and APT SKY PLUS?

APT SKY raises GH only, leaving KH and pH unchanged — better for tetras and soft-water plants. APT SKY PLUS also raises KH and buffers pH, better suited to guppies, mollies, and snails.

How much APT SKY PLUS should I use for RO water?

Start with 15 ml (10.5 g) per 60 litres, then test and adjust based on your target GH and KH.

Does APT SKY PLUS affect NPK or plant fertilization?

No, it has no effect on NPK values, so it won't interfere with your regular fertilization routine.

Pairs Well With

• APT 3 or APT 1 – for plant fertilization
• APT Start – when setting up a new aquarium with RO water