Battling mustard algae in my pool, any great ideas?

The algae in your pool is becoming less sensitive or building an imminity to the type of chlorine or shock that you are using. You need to try something different, I recomend Yellow Out. Youll need to raise your pH above 8.0 than add 2lbs Yellow Out and follow that up with equal parts of chorine (it will have a chemical reaction similar to mixing baking soda and vinegar). Then circulate your pool for 24 hrs. Algacides don't kill the algae that just open up the spores of the algae and make them more susceptable to the chlorine.

The sand in the filter may have become ineffective so changed the sand and ran the filter for twenty-four hours and it should cleared right up. The sand in a sand filter can lose its edges over a few years of being in a filter so the contaminants just pass right through it and back into the pool, but to be safe, ask your pool store pro too.

I bought some stuff called Yellow Kill or something. It is especially formulated for green and yellow alge. Make sure you brush the sides before the application it really helps.

super shock it!