Seachem Reef Builder (1.3 lbs)

by Seachem

$30.99 (You Save 48%)
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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.

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
UPC 000116036306
SKU 363
Item Number L1702890913P17028
Size 1.3 lbs
Weight 1.5 lbs.
Pkg Dimensions 10" (L) x 4" (W) x 5" (H)

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Reviewed by Candice K. on Jul 12, 2021

Reviewed by Gena B. on Apr 23, 2021


Reviewed by Steven K. on Jan 31, 2021

The product should be call "The come back kid"

Reviewed by Pamela M. on Dec 25, 2020

For better corals, use this!

Reviewed by Dolphus S. on Dec 16, 2020

Good value, consistent effect

Reviewed by Sue F. on Dec 9, 2020

Five Stars

Reviewed by Jay Goldberg on Dec 5, 2020

Work Great!!

Reviewed by matthew C. on Nov 10, 2020

stabilize and raises alkalinity

Reviewed by Marianne F. on Oct 21, 2020

Works as advertised

Reviewed by Carmen S. on Oct 15, 2020

Cheap and dependable

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