** Shares of CYAN.O fall 18 pct to $4.15, worst pct fall
since Feb 2016; second-biggest pct loser across U.S. exchanges
** The microalgae nutritional supplements maker says
production costs have and will rise during Q4 and in Q1 of FY19
(https://bit.ly/2vr7FR9)
** Co says hurt by adverse effect on Spirulina production
due to insufficient fresh water supply
** About 19.9k shares traded, ~3x their 30-DMA
** Shares up 6.3 pct YTD
(Reporting by Shreyashi Sanyal in Bengaluru)
((RM: Shreyashi.Sanyal.thomsonreuters.com@reuters.net))