Foundation B KH/Alkalinity 1kg — Buffer Powder for Reef Tanks - Red Sea

Foundation B KH/Alkalinity powder from Red Sea is the complex of carbonate and seawater buffers in dry form. 1kg bag. It is the powder in the trio where the strength gap with the liquid is widest — and the easiest one to get caught by.

⚠️ Three different strengths carry the name "Foundation B"

This is the most important thing on this page. Red Sea publishes three distinct values, and confusing them leads to errors of a factor of three:

• Dry powder: 1g raises alkalinity in 100 litres by 0.12 meq/l (0.33 dKH)
• Ready-to-use liquid: 1ml raises alkalinity in 100 litres by 0.036 meq/l (0.1 dKH)
• Stock solution made from this powder: 1ml raises alkalinity in 100 litres by 0.012 meq/l (0.034 dKH)

Read that third line carefully: the stock solution you mix yourself is three times weaker than Red Sea's liquid bottle. A reef keeper switching from the liquid to their own solution while keeping the same dose under-doses alkalinity threefold — and spends weeks wondering why the KH will not climb.

Making your stock solution

Red Sea's recipe: 100g of powder per litre of RO water. A 1kg bag therefore yields 10 litres of stock solution — by far the best yield of the three Foundation powders. Dose it by the figure above (0.034 dKH per ml per 100L), not by the shelf liquid's figure.

What alkalinity actually measures

Alkalinity is not "the carbonate level": it measures every buffering substance in the water — bicarbonate (HCO₃), carbonate (CO₃), hydroxide (OH) and borate (BO₃). Red Sea advises avoiding test kits that measure carbonates only. Conversion: dKH = meq/l × 2.8.

Specifications

• Composition: carbonate and other seawater buffers
• Powder concentration: 1g raises alkalinity in 100 litres (25 gal) by 0.12 meq/l (0.33 dKH)
• Stock solution: 100g per litre · 1kg yields 10L
• Daily maximum: 0.5 meq/l, or 1.4 dKH per day
• Sizes: 250ml, 500ml, 1L, 5L liquid · 1kg powder (this listing)
• Suitable for: SPS, LPS and soft coral reef tanks

Target levels for your reef tank

Three rules not to skip

• Daily maximums: alkalinity 0.5 meq/l (1.4 dKH), calcium 20ppm, magnesium 10ppm.
• Dosing order: magnesium, then alkalinity, then calcium — 10 minutes between each.
• Where to add it: into the sump, or slowly into a high-flow area.

Classic trap: adding buffer to a tank whose calcium is already at saturation causes precipitation and drops the calcium. Test first.

Goes well with

Alkalinity that refuses to hold often traces to low magnesium: check with Foundation C Magnesium 1kg before raising the buffer. And buffer builds nothing without calcium — Foundation A Calcium+ 1kg completes the powder trio.

If you would rather not mix anything, Foundation B 1L liquid doses as-is.

Frequently asked questions

Is the powder stronger than the liquid?

Yes: 1g of powder raises alkalinity by 0.33 dKH per 100L against 0.1 dKH for 1ml of liquid. But note the stock solution you make from it is three times weaker than the shelf liquid.

How much solution does a 1kg bag make?

10 litres, at 100g per litre of RO water. That is the best yield of the three Foundation powders.

Can I dose my stock solution like the Red Sea bottle?

No, and this is the most common error. The stock solution gives 0.034 dKH per ml per 100L against 0.1 dKH for the bottled liquid. You need roughly three times the volume.

How much can I raise alkalinity in one day?

By 0.5 meq/l at most, which is 1.4 dKH.

Why buy from ReefSolution

Aquarium ReefSolution is an authorized Red Sea dealer. Our team works in marine aquariums in Laval and knows the Reef Care Program from real tanks. We ship across Canada and offer in-store pickup.