We have found at our store the Elos Expertline ExtraVitamin to work the best at raising your vitamin levels. This product is a European product and because of this the directions are not 100% clear for us in the USA. Here is a simplified set of direction that I hope you will find useful.
Although vitamins are only one of a variety of components of a healthy diet, your ornamental fish and invertebrate requires vitamins for survival. Whereas the quantity of vitamins supplied to the fish with ELOS SV, ELOS OMEGA and PRO SKIMMER range is sufficient in most situations your fish require an extra portion of vitamins in some stages, like when frozen fish food is used for feeding, in stress situations caused by transportation, relocation, and acclimatization to the aquarium, during and after pharmaceutical treatment in order to support spawning maturity of mainly vitamin C and E, and for the raising of young fish.
Elos Extra Vitamin can be add directly into the freshwater or saltwater aquarium or to mix with the food supply
US Gallon Conversion: Elos Extra Vitamin may be 3-5 drop per every 7 gallons once a week or when setting up a new tank, water changes or adding new fish or corals. You also add to frozen or dry food 3-5 drops per meal for new fish, stressed fish or fish coming out of a chemical quarantine system.
Metric Dosing: Elos Extra Iodine may be dosed as much as needed to maintain correct levels. Dosing is 3-5 drops per 25 Lt of water or 16-20 drops per 100 Lt.
Ensure that Magnesium and Calcium are within specifications also. When using in a Balling method you will need to figure amount of absorption and adjust amount as needed to maintain correct levels. If using all 6 Elos Expertline supplements water changes may be reduced in frequency to as little as 1 time every 3 months or less. Use extreme caution when attempting major changes in a short time this is best left for experts.