What kind of media are you using in you penguin filter?Sponges,filter floss,etc. will all go "biological" on you and lead to excess Nitrate.Nitrate is a nutrient for many types of algae.The problem could be with your filter.
IMO,you will need at least 3 PH's in a tank that size.Proper water flow in a reef tank is one of the most important things you can provide.With proper current,the natural "bio-filter" of the LR and LS becomes more efficient.