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Engineered Seawater Salt | ≥99.5% ionic consistency between batches regardless of volume mixed.

C8R Spread Formul8 Reduced.bmp

Shown: Formul8 in Reef Blueprint packaging. L to R: Formul8 ASW, Formul8 Reef, Formul8 RSW. Commercial packaging options are available for users not requiring a shelf presentation.

Formul8 engineered salt formulations strictly utilize materials with purity not less than that which conforms to FCC grade for major components, and ACS-Reagent grade for minor components.  Due to the purity of components utilized, all Formul8 variants mix to ≥99% clarity of purified water utilized in the seawater preparation.  Ionic consistency between containers generally exceeds 99.5%.  Formul8 blends do not deposit residue on static surfaces, such as mixing vessels and pipes.  Recommended applications for Formul8 blends are: aquaculture; zoological displays; and scientific research projects demanding the greatest purity of components, homogeneity of blend, and accuracy of ionic values, such as in lab sea surface temperature ​analysis and biotope reproduction.

Ionic consistency between batches produced by the aquarist or technician is determined by the accuracy of measurements made of the four individual components.  Accurate component measurements yield nearly 100% ionic consistency between batches, making pre-testing newly-mixed seawater to determine concentrations of important ions such as Mg and Ca unnecessary (the values are consistent every time, regardless of volume of seawater prepared, when targeting a specific salinity value).

We produce three variations of the Formul8 series, namely ASW, Reef, and RSW, corresponding with open ocean seawater values (S=35.2), enhanced coral grower values (S=35.4), and Red Sea values (S=40.1), respectively.  For quick reference, ionic composition of these formulations is presented in the table below.  Hyperlinks lead to the dedicated product pages and provide additional details regarding usage.


  • Salinity

  • pH average

  • Alkalinity average

  • Chloride

  • Sulfate

  • Sodium

  • Magnesium

  • Calcium

  • Potassium

  • Bromide

  • Strontium

  • Boron

  • Fluoride

  • Rubidium

  • Iodide

  • Molybdenum

  • Vanadium

  • Nickel

  • Zinc

  • Manganese

  • Copper

  • Selenium

  • Iron

  • Cobalt


8.35 +/-0.050

5.70 dKH / 8.00 dKH*

19,313.69 ppm

2,712.36 ppm

10,783.84 ppm

1,283.72 ppm

412.10 ppm

399.10 ppm

67.23 ppm

7.94 ppm

4.45 ppm

1.298 ppm

1.197x10-1 ppm

5.584x10-2 ppm

1.055x10-2 ppm

2.000x10-3 ppm

4.695x10-4 ppm

3.925x10-4 ppm

2.747x10-4 ppm

2.542x10-4 ppm

1.342x10-4 ppm

5.585x10-5 ppm

1.768x10-6 ppm


8.35 +/-0.050

8.00 dKH

19,392.43 ppm

2,712.36 ppm

10,678.70 ppm

1,347.91 ppm

432.70 ppm

419.06 ppm

67.23 ppm

8.34 ppm

4.45 ppm

1.298 ppm

1.197x10-1 ppm

5.584x10-2 ppm

1.055x10-2 ppm

2.000x10-3 ppm

4.695x10-4 ppm

3.925x10-4 ppm

2.747x10-4 ppm

2.542x10-4 ppm

1.342x10-4 ppm

5.585x10-5 ppm

1.768x10-6 ppm


8.35 +/-0.050

9.11 dKH

21,934.01 ppm

3,080.35 ppm

12,246.91 ppm

1,457.89 ppm

467.99 ppm

453.25 ppm

76.35 ppm

9.02 ppm

5.05 ppm

1.471 ppm

1.357x10-1 ppm

6.332x10-2 ppm

1.196x10-2 ppm

2.267x10-3 ppm

5.443x10-4 ppm

5.669x10-4 ppm

3.402x10-4 ppm

1.134x10-4 ppm

1.521x10-4 ppm

6.236x10-5 ppm

3.402x10-6 ppm

*Captiv8 Aquaculture-branded ASW formulation: 5.70 dKH; Reef Blueprint-branded ASW formulation: 8.00 dKH.

Astute observers will notice that the minor and trace elements incorporated into these formulations are those which are specifically demonstrated by oceanographic researchers to exhibit nutrient-type depth profiles, and which are not considered phytotoxic at NSW values; this list conforms with our minor and trace element solution, Isol8 MT, which is intended to be dosed into recirculating seawater systems as a means of maintaining NSW values, at the daily rate of 1 mL / 250 gallons, or 1 drop (0.05 mL) per 12.5 gallons.

Lanthanide metals (Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, and Lutetium) are not incorporated into these formulations; this decision has been made as a result of the considerable body of evidence which shows that these elements, collectively, are phytotoxic in concentrations which are at or below those of their respective NSW values (assuming S=35.0).  Additionally, barium and chromium salts are excluded on grounds of contact toxicity.

All variants of the Formul8 series incorporate sodium chloride, not the case with our Formul8x series which requires that the user add their own, locally-sourced sodium chloride in order to create a complete seawater analog.  For those interested, we use FCC-grade Morton Purex, not TFC Purex (which contains an anti-caking agent, Yellow Prussiate of Soda, aka Sodium ferrocyanide), in the Formul8 series.  Average purity of FCC-grade Morton Purex exceeds 99.75%.  For reference, sodium chloride purity must be above 99.0% in order to qualify as USP-grade.

We offer the service of producing customized engineered salt blends for those interested.  Clientele may dictate that the formulation follows seawater composition as recorded by a specific researcher, collaborative team, or lab.  There are many such analyses published.  Published values generally reflect open ocean ionic composition (Arctic, Atlantic, Indian, Pacific, Southern Ocean, and marginal seas with ionic composition similar to open ocean values, herein collectively referred to as "average seawater").  Because the values for all ions tend to vary less than 2% (S=35) in these reports (even dating back to the 1960's), we do not feel that there is much practical difference in outcome of using one report vs another as a basis for an engineered seawater salt.  Be that as it may, we do not recommend any one single report to follow as a basis for reproducing average seawater chemistry.  Interested parties are directed to any appropriate peer-reviewed literature published within the last five years which includes a comprehensive analysis of seawater using modern analytical methods, bearing in mind that the individual values published are sometimes a compilation of ion-specific analyses performed by individuals and labs.

If the client's objective is to have a formulation created which features an elevated or reduced concentration of one or more ions relative to their average seawater values, then the procedure is simply to provide us with the target values for those ions.  We are able to formulate and produce a blended salt which conforms to practically any requirements, with variance of ≤0.01%, assuming one degree of freedom (chloride in most cases, though sulfate can sometimes be used).

Similarly, it is possible to formulate and produce an engineered seawater salt which accurately recreates the chemical composition of marginal seas with ionic values which do not conform to average seawater.  Examples are the Mediterranean Sea and Black Sea.

Custom formulations may include or omit bromide, as dictated by the system design and absence or presence, respectively, of ozone injection; this aspect is user-defined.

Interested parties are provided a questionnaire which identifies the system requirements and user-specified ionic values.  A quotation is provided which reflects the total cost of production, using current material and labor costs.  Included is a Sigma-T reference table for the desired water temperature, as well as the volume of seawater which the formulation will produce at various salinity values.  The quotation is effective for thirty (30) days from the date of issue, unless otherwise specified.  The minimum order for production of a custom formulation is twenty (20) pounds.  Note that the client is purchasing the blended product, not the formulation.  Formulations remain the express property of Captiv8 Aquaculture.

A general discussion on artificial seawater and aspects of sea salt composition considerations may be found here.


Notice: It is not possible to eliminate all risks associated with the use, handling, or storage of this product. Ineffectiveness, injury to crops and/or livestock, or other unintended consequences may result due to factors outside the control of Captiv8 Aquaculture or the seller. Buyer or user shall assume all such risks. For details, go to Terms and Conditions. Consult SDS before use.


Disclaimer: Captiv8 Aquaculture warrants that this product conforms to the description, and is reasonably fit for the purposes described, on its label. In no event shall Captiv8 Aquaculture or the seller be held liable for any incidental, consequential, or special damages, loss, or injury, including, without limiting, lost profits, resulting from the use or handling of this product. The exclusive remedy of the buyer or user for all claims shall be the return of the purchase price of this product. Express and implied warranties are disclaimed. Captiv8 Aquaculture does not authorize any agent or representative to make any other warranty, guarantee, or representation concerning this product.

For sale by Captiv8 Aquaculture and its authorized dealers, only.

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