2Hr Aquarist APT Sky enables shrimps and hardwater plants to thrive with softwater plants

2Hr Aquarist APT Sky is a GH booster that raises GH without altering NPK, KH or pH

2Hr Aquarist GH Booster, APT Sky, allows for hardwater and softwater plants to thrive together

Vendor:The 2Hr Aquarist

2Hr Aquarist APT SKY PLUS

Q: How do I use APT SKYPLUS? Can I pre-mix it or run it through a doser?

Add APT SKYPLUS directly to your tank, or better, to the fresh water you use for a water change, and let it circulate. It's made of calcium and magnesium salts, which have low solubility, so it can't be concentrated into a small stock solution or added through an automatic doser. It needs a large body of water to dissolve fully. Dose to your target GH. Most planted tanks do well at around GH 6, and our dosing calculator gives you the exact amount for your tank volume.

Q: Do I need APT SKY, and should I choose SKY or SKYPLUS?

You need a remineraliser if you run RO/RODI water, or naturally very soft tap water that's low in GH. If your tap water is already moderately hard, you likely don't need one. Between the two: APT SKY raises GH only (calcium and magnesium) and leaves KH and pH untouched, which suits most planted tanks and soft-water, acidic-loving fish. APT SKYPLUS raises both GH and KH (and nudges pH up slightly), so choose it if your fish or shrimp need a specific, stable KH.

Q: What TDS should I target?

As a rough guide, RO water remineralised to 5–7 dGH usually sits somewhere around 110–150 TDS. But TDS isn't the best way to dose accurately. The reliable method is to dose APT SKYPLUS by weight, using an accurate weighing scale, rather than by volume or by chasing a TDS reading. TDS only reports the total dissolved ions in your water as a single combined number. It doesn't tell you which ions are present or in what ratio, and readings shift with your meter, its calibration, and whatever is already dissolved in the tank. That makes it useful for tracking relative changes over time, such as watching TDS climb between water changes, but unreliable as an absolute target. Weighing your dose gives you a precise, repeatable result every time.

€16,90

2Hr Aquarist APT SKYPLUS comprehensively replenishes vital minerals in RO/ RODI water without negatively altering NPK. Moderately raises KH to ~2 dKH and pH to 7.2~7.6
Enables shrimps and hardwater plants to thrive together with softwater plants*.

INSTRUCTIONS

15ml per 60L (0.5oz / 16 US gal) of RO/RODI water.

Each 3.5g / 5ml per 60L adds 9ppm Ca and 2.5ppm Mg (+1.8dGH, +0.5 dKH)
*To grow softwater plants, RO/RODI water recommended if tap water measures >2 dKH

WHY

APT SKYPLUS resolves the key conundrum of how to increase water hardness (specifically as a GH booster) without altering NPK values (which interfere with the calibrated ratios of fertilizers). It moderately raises KH to ~2dKH, within the band still favored by most commercial aquatic plants.

INGREDIENTS

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

Product variants

Precision GH Boost

Most conventional GH boosters inadvertently alter NPK values, interfering with calibrated fertiliser ratios. They also raise pH and KH to levels that most commercial aquatic plants don't favour. APT surgically raises GH without these side effects.

Grow Anything

Some plants thrive in mineralized "hardwater," while others prefer acidic "softwater." APT SKY and SKYPLUS make it easy to satisfy both preferences.

Designed for Shrimp

Caridina and Neocaridina shrimp need higher calcium levels, which are naturally absent in acidic softwater environments. APT SKY or APT SKYPLUS lets you build a thriving shrimp community with acidic aquasoils.

Baseline

If you have soft water or use RO water, simply add 15ml per 60L (16 US gal).

If you have hard water or are unsure, obtain a GH reading with a common test kit. You can also read your local water report as we describe here.

Dosage

Use the Dosage Calculator (below) to determine dosage. For the very first dose, Water Volume = tank's water volume. GH Reading is your tank's GH level.

Subsequently, during water change, Water Volume = Volume of new tap water added. GH Reading = tap water GH level.

Sprinkle Directly

Simply add APT SKY / SKYPLUS powder directly into the tank. It is OK if it covers the plants. Another way is to first mix APT SKY / SKYPLUS with some water in a small container, then add the milky solution to the tank. Both are equally fine.

SKY or SKY+?

APT SKYPLUS raises KH moderately to ~2 dKH and buffers pH to 7.2~7.6. APT SKY leaves KH and pH unchanged. Use APT SKYPLUS if you keep guppies, mollies and snails. Use APT SKY if you keep tetras and rare softwater plants. Both are great for shrimp. A more detailed comparison can be found here.

3X Power

As a GH booster, APT SKY is ~ 3X as concentrated as conventional remineralisers. Each 3.5g / 5ml per 60L adds 12ppm Calcium and 3.5ppm Magnesium, raising GH by 2.5 dGH. Did we mention that it is super-soluble, non-caking, and just a joy to handle?

Freedom to Play

Plants have conflicting softwater / hardwater requirements. APT SKY and APT SKYPLUS remove the hassle of having to choose between softwater and hardwater plants. For softwater tanks, it boosts shrimp health and reproduction. The catch? It does require Softwater or Reverse Osmosis (RO) water to begin with. At the moment, there is no easy way to make Hardwater ’Soft’.

FAQs

Please read our FAQs page to find out more.

How do I use APT SKYPLUS? Can I pre-mix it or run it through a doser?

Add APT SKYPLUS directly to your tank, or better, to the fresh water you use for a water change, and let it circulate. It's made of calcium and magnesium salts, which have low solubility, so it can't be concentrated into a small stock solution or added through an automatic doser. It needs a large body of water to dissolve fully. Dose to your target GH. Most planted tanks do well at around GH 6, and our dosing calculator gives you the exact amount for your tank volume.

Do I need APT SKY, and should I choose SKY or SKYPLUS?

You need a remineraliser if you run RO/RODI water, or naturally very soft tap water that's low in GH. If your tap water is already moderately hard, you likely don't need one. Between the two: APT SKY raises GH only (calcium and magnesium) and leaves KH and pH untouched, which suits most planted tanks and soft-water, acidic-loving fish. APT SKYPLUS raises both GH and KH (and nudges pH up slightly), so choose it if your fish or shrimp need a specific, stable KH.

What TDS should I target?

As a rough guide, RO water remineralised to 5–7 dGH usually sits somewhere around 110–150 TDS. But TDS isn't the best way to dose accurately. The reliable method is to dose APT SKYPLUS by weight, using an accurate weighing scale, rather than by volume or by chasing a TDS reading.

TDS only reports the total dissolved ions in your water as a single combined number. It doesn't tell you which ions are present or in what ratio, and readings shift with your meter, its calibration, and whatever is already dissolved in the tank. That makes it useful for tracking relative changes over time, such as watching TDS climb between water changes, but unreliable as an absolute target. Weighing your dose gives you a precise, repeatable result every time.

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