Vitamin C Powder has been known to stimulate corals especially Zoanthid and Palythoa when dosed on a regular basis. Many people have noticed an increase in size and growth along with improved coloration while dosing Vitamin C. It is also aids in the reduction of closed polyps and fungus.
We dose this Vitamin C on our tanks and have found the best way is to use a cheap (~$15) Automatic Fish Feeder.
How Vitamin C dosing is helpful is not difficult to study. As it is Vitamin C is a vital nutrient which might not be accomplished though other sources hence the organisms remain deprived of an essential element that can boost up growth and health. Corals benefit a lot more their addition in tank. Not only re their color enhanced and protected but their growth also is seen to flourish in presence of Vitamin C. Zoanthid are known to develop best under its effect; both growth-wise and color-wise. It also enhances rejuvenation of leather corals after fragmentation. Those corals refusing to open up due to fungal infections are also found to have shown positive response on dosing of Vitamin C. Since Vitamin C is also a form of carbon dosing it effect are more prominent in absorbing wastes and extra nutrients in tank. Carbon is consumed by the good bacteria that grow and consume all the nuisance substances like nitrite and phosphate. Some small polyp stony corals that have a tendency to thrive better in low nutrient tank, show good bloom and blush in presence of Vitamin C doses.
For the normal benefits of the tank like absorption of excess nutrients and thriving of corals a small dosage of 5ppm or even lower should be enough. However, if your aim is to treat Zoanthids that have closed up for a longer duration due to stress or fungal infections, it is recommended that you add 30ppm of Vitamin C for this purpose. Rejuvenation of fragmented leather coral can also do well with the 5ppm dosing and not more is needed. Though no bad effect of extra dosing has been found, it is best to begin with small doses and increase slowly over the weeks following. Vitamin C is said to degrade hurriedly when exposed to light and water. Therefore instead of dosing at once, split in two doses per day. This way the first half will be depleted and not the entire added content. Add the first dose in the morning and the second at night. The container of Sodium Ascorbate should be kept in a cool, dry, dark place to avoid dilapidation of the product.