Brightwell Aquatics

SpongExcel - Silica solution for improved growth rate of Sponges, Bivalves, and Gastropods



  • Ionic silica solution for enhancing growth rates of sponges and gastropods.
  • 1 drop per gallon of water increases ionic silica concentration by ~0.20 ppm.
  • May be employed in silica-limited systems stocked with sponges to improve water quality by increasing the rate of natural latent organic material uptake by these organisms.
  • May be used to increase the rate of sponge growth in marine systems housing spongivorous fishes such as marine angelfishes, butterflyfishes, and their allies, providing them with greater access to their natural foods.
  • Formulated by a marine scientist.



60ml | 125ml | 1L | 20L

Technical Background

Silica is an important nutrient in seawater; it is required by many organisms (primarily diatoms and sponges
in terms of total silica uptake) for the production of biomass, and is linked with the uptake of other nutrients, such as nitrogen and phosphorus, by these organisms. Sponges and diatoms can be significant nutrient sinks, and marine aquaria stocked with sponges, in particular, can benefit with the controlled addition of a silica solution. The natural seawater concentration of total silica is ~2.8 ppm, however this concentration varies by depth and region and is
likely to be excessive in most marine aquaria. Rather than attempt to maintain this concentration in an aquarium, it is advisable to begin at a very low concentration (e.g. 0.05 ppm) and gradually increase this with time as the rate of silica uptake in the system dictates. Systems with considerable sponge growth tend to be silica-limited, therefore maintaining a silica concentration of ~1 - 2 ppm is likely to be of benefit. Additionally, diatom growth may have
a significant impact on the rate of natural latent organic material uptake and recycling in marine aquaria, leading to improved water quality; diatoms are also a valuable food source for various grazing fishes and motile invertebrates. We are certainly not advocating that diatoms should be encouraged to grow unchecked in order to help improve water quality, however these organisms, in addition to sponges, can be a valuable part of a natural ecosystem
that converts latent organic material into desirable biomass and supports greater biodiversity in closed marine aquaria through the maintenance of diatom- and sponge-grazing organisms.

Instructions and Guidelines

Determine the silica concentration in the aquarium using an accurate test kit before supplementing. Identify all sources of silica in the aquarium (e.g. fresh water, salt mix, etc.) before determining a rate of dosing for this
supplement. Begin with a dosage of 1 drop per 20 US-gallons per day, which will increase the silica concentration in this volume by ~0.01 ppm. Observe sponges for signs of growth improvement for at least two weeks, which may be significant enough to notice within the first week of dosing. Allow two weeks at this dosage before increasing the dosing volume; increase dosage by up to 10% per week as the perceived silica requirements of the organisms dictate. Maintaining the silica concentration in a range of 0.5 - 2.0 ppm will generally suffice for most systems; in general, the greater the biomass of silica-dependant organisms and the more available other necessary nutrients are, the greater the demand for soluble silica becomes. If diatom growth becomes abundant, discontinue dosing for 3 - 4 days and then resume dosing at a lower dosage. Note that daily, rather than less frequent, dosing is strongly recommended, as adding a large amount of soluble silica to any marine aquarium all at once is highly likely to result in a diatom bloom. Each ml of Brightwell Aquatics SpongExcel will increase the concentration of soluble silica [SiO2] in 1 US-gallon (3.785 L) of water by ~4 ppm, or ~0.20 ppm per drop. Determine the required daily dosing rate (recommended to weekly dosing) by measuring the aquarium's [SiO2] at the same time each day over a one- to two-week period. Estimate the volume of water in the entire aquarium system; divide the daily decrease in [SiO2] by 0.20; multiply this number by the volume of water in the system to get the daily dosage required (drops) to maintain a table

Caution: Silica solutions are caustic; in case of contact flush skin and/or eyes with fresh water for 15 minutes. Drink 16-oz. fruit juice if swallowed and seek immediate medical attention. Wear protective eyewear and gloves when handling. Keep out of reach of children. Not for human consumption.