2Hr Aquarist APT SKY Plus

APT Sky Plus

APT Sky Plusis the close cousin of APT Sky — a remineralizer that restores the calcium, magnesium, trace minerals, and natural seaweed extract that soft or RO water lacks, all without disturbing the nitrogen, phosphorus, and potassium your fertilizer is calibrated around. The difference is in the carbonate side of the equation: where plain Sky leaves KH and pH untouched, Sky Plus also nudges KH up to around 2 dKH and gently buffers pH into the 7.2–7.6 range. That small amount of buffering guards against the sharp pH swings that very soft, aquasoil-driven tanks are prone to.

At Cuboid, the APT range is what we run in our own aquascaping display tanks — products we use ourselves day in and day out, and recommend without hesitation to anyone serious about a planted aquarium.

Sky or Sky Plus?Reach forSky Plusif you keep livestock that appreciate a little hardness and stability in the water — 2HR recommends it for those keeping “guppies, mollies and snails,” and for anyone worried that aquasoil is driving pH too low. Choose plainSkyfor tetras and rare softwater plants that want KH kept at rock bottom. Both are shrimp-safe and both leave your fertilizer ratios intact.

The result is a tank where softwater and hardwater plants can share the same water, shrimp get the steady minerals they need to molt and breed, and your pH holds rather than drifting. It still asks for soft or RO water to start — like any remineralizer it adds minerals rather than removing them — but within that range it gives you a more forgiving, better-buffered version of SKY-boosted water. And like the rest of the line, it’s designed to work alongside your APT fertilizers.

Dosing Guidelines:Sky Plus is the same super-soluble, non-caking powder as Sky, just a touch milder per scoop. A simple starting point:one 5 ml scoop (about 3.5 g) per 10 gallons raises GH by roughly 3 dGH (about 53 ppm) and lifts KH slightly toward ~2 dKH.Most planted tanks are happiest around 5–7 dGH (90–125 ppm), so scale to your tank and top up at each water change. For an exact amount matched to your water, 2HR Aquarist’s free online APT Sky Plus dosing calculator does the math for you.