Seachem Reef Builder

by Seachem
$27.99 (You Save 46%)
In Stock
1.3 lb

10.6 oz 1.3 lbs

Boost Your Reef's Health

Elevate your marine aquarium's alkalinity with this trusted formula, which promotes coral growth without affecting pH. Keep your underwater ecosystem thriving with an easy-to-use supplement for optimal reef structure.

Seachem Reef Builder Photo 1
Seachem Reef Builder Photo 2

Maintain Aquarium Alkalinity

Achieve the perfect aquatic balance with this blend that enhances coral growth. This product is the cornerstone to a robust, vivid marine habitat, ensuring the longevity and beauty of your reef.

Key Features

  • Raises carbonate alkalinity (KH) with minimal pH impact
  • Provides a blend of carbonate sources that will not lower pH
  • Will not deplete calcium, magnesium, or strontium
  • Promotes healthy coral growth
  • Raises carbonate alkalinity (KH) without immediate impact on pH
  • Longterm use stabilizes pH at 8.3
  • Does not deplete?calcium, magnesium, or strontium
  • Promotes healthy coral growth

Seachem Reef Builder 1.3 lbs

Seachem Reef Builder supplies the carbonates and calcium which are essential for all coral growth. It also raises carbonate alkalinity without immediately impacting water pH, and will stabilize aquarium water at pH 8.3 with long term use.

  • Raises carbonate alkalinity (KH) with minimal pH impact
  • Provides a blend of carbonate sources that will not lower pH
  • Will not deplete calcium, magnesium, or strontium
  • Promotes healthy coral growth

If either calcium or carbonates become deficient, coral growth will cease, followed by a rapid decline in coral health. Used as directed, Seachem Reef Builder will not deplete calcium, magnesium, or strontium which usually tend to precipitate with increasing alkalinity.

Seachem Reef Builder and Reef Buffer may be used together: use Reef Builder to raise carbonate alkalinity without affecting pH, and use Reef Buffer to raise carbonate alkalinity and pH. As a general rule, reef alkalinity should be maintained at 3–5 meq/L (8–14 dKH); alkalinity should not be allowed to fall below 2 meq/L.

BEGINNER: Use 3 g (1/2 level teaspoon) per 150 L (40 gallons) twice a week. Dissolve in at least 250 ml (1 cup) of freshwater. Check alkalinity every 2 weeks and adjust amount or frequency accordingly. For precise dosing, use the Seachem Digital Spoon Scale.

ADVANCED: Check alkalinity, then follow addition regimen above until alkalinity is adjusted to 4–5 meq/L. Each 3 g/150 L will raise alkalinity by about 0.25 meq/L. Quantity or frequency can be adjusted, but do not exceed 12 g/150 L per day. Thereafter, use as required to maintain alkalinity.

EXPERT: After determining the alkalinity consumption rate, set up a continuous drip system. Use the following formula to determine how much to add to your top–off water: m=0.08va (m=grams to add to top off water, v=volume of tank in liters, a=amount to raise alkalinity in meq/L). For example, if you want to raise your alkalinity by 1 meq/L in a 200 liter tank, then you would add 0.08x200x1=16 g into the top–off water. [For reference: 1 gallon=3.8 liters, 6 g=1 teaspoon].

DO NOT OVERDOSE: Excess alkalinity may enhance the loss of calcium, magnesium, and strontium. Do not directly mix with any calcium, magnesium, or strontium supplement. Best if calcium and carbonate additives are added on alternate days or at least 30 minutes apart.


Brand Seachem
Size 1.3 lb
Weight 1.5 lbs.
Pkg Dimensions 6.5" (L) x 3" (W) x 3" (H)
UPC 000116036306
SKU 363
Product Code PE00090911D83P17028

Customer Reviews

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Reviewed by Candice K.

Reviewed by Gena B.


Reviewed by Steven K.

The product should be call "The come back kid"

Reviewed by Pamela M.

For better corals, use this!

Reviewed by Dolphus S.

Good value, consistent effect

Reviewed by Sue F.

Five Stars

Reviewed by Jay Goldberg

Work Great!!

Reviewed by matthew C.

stabilize and raises alkalinity

Reviewed by Marianne F.

Works as advertised

Reviewed by Carmen S.

Cheap and dependable

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