Foundation ABC+ 1kg — All-in-One Powder for Reef Tanks up to 300L - Red Sea

Foundation ABC+ from Red Sea is a single powder holding every element of Calcium+, KH/Alkalinity and Magnesium, plus those of Trace Colors Iodine+ and Potassium+: calcium, strontium, barium, bicarbonates, magnesium, potassium, boron, iodine and bromine — in the exact ratio found in coral skeleton. 1kg bag.

Red Sea explains the Foundation program in its own words:

And for a longer walk-through of the whole Reef Care Program — major elements, trace elements, algae management and coral nutrition — this independent explainer covers the ground well:

The thinking behind the all-in-one

Red Sea's research shows the ratio between these elements stays fairly constant from one coral species to another. By supplying them all in a fixed ratio, dosed to measured calcium uptake, you cover the corals' metabolic demand with one product and one weekly test instead of three.

Red Sea recommends ABC+ for aquariums up to about 300 litres (75 gallons). Beyond that, the individual supplements give finer control.

⚠️ Three limits to know before buying

This product carries strict usage rules that Red Sea states plainly. They are not optional.

• Never more than 60g at one time, regardless of system size. A larger dose is given in spoonfuls spaced 10 minutes apart, so the powder dissolves without causing precipitation.
• Never use it to make a one-off calcium correction. ABC+ is a daily maintenance supplement. For adjustments, use the individual supplements.
• Add it directly to the sump, never dissolved in top-up water.

A fourth, subtler point: the iodine and potassium in ABC+ should only be supplemented according to their own measured uptake. If you already dose Trace Colors, account for it so you do not double up.

How to dose

ABC+ is dosed daily, according to measured calcium uptake. To find yours:

1. Bring calcium, alkalinity and magnesium to their target values.
2. Run 4 days without dosing anything, topping up evaporation with fresh water.
3. Test, work out the dose to return to target, add it.
4. Divide by 4: that is the daily dose for the week.

Over time an imbalance can appear between the three foundation elements despite the fixed ratio. Red Sea asks you to test all three weekly and correct any drift with the individual Calcium+, KH/Alkalinity and Magnesium supplements.

The bag ships with two measuring spoons: 20g and 2g.

Specifications

• Elements: calcium, strontium, barium, bicarbonates, magnesium, potassium, boron, iodine, bromine
• Recommended tank size: up to about 300 litres (75 gal)
• Maximum single dose: 60g
• Spoons included: 20g and 2g
• Size: 1kg powder
• Suitable for: SPS, LPS and soft coral reef tanks

Red Sea publishes no "1g raises calcium by X ppm" figure for ABC+, unlike the individual powders. That is consistent: the product is built to be dosed on measured uptake, not on a conversion calculation. If you see such a figure elsewhere, it did not come from the manufacturer. The dosing chart is on the back of the bag — write to us if you need help reading it, with your tank's net volume and your latest readings.

Target levels for your reef tank

Daily maximums to respect: calcium 20ppm, alkalinity 0.5 meq/l (1.4 dKH), magnesium 10ppm.

Goes well with

ABC+ does not replace the individual supplements, it complements them: Red Sea expressly asks you to correct weekly drift with Foundation A Calcium+, Foundation B KH/Alkalinity and Foundation C Magnesium. Keep them on hand.

Since ABC+ already covers iodine and potassium, if you add Trace Colors ABCD, dose those two elements to their measured uptake so you do not double the input.

Frequently asked questions

Does ABC+ replace the three Foundation supplements?

Day to day yes, for a tank up to about 300 litres. But Red Sea asks you to test all three elements weekly and correct drift with the individual supplements. ABC+ maintains; it does not correct.

How much can I add at one time?

60g at most, whatever the tank size. A larger dose goes in as spoonfuls 10 minutes apart to avoid precipitation.

Can I dissolve it in my top-up water?

No. Red Sea asks that it be added directly to the sump.

My tank is over 300 litres — can I still use it?

Red Sea recommends it up to about 300 litres. On a larger volume the individual supplements let you adjust each element separately, which matters once uptake gets significant.

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.