What are the white suds on the pool water?

Without seeing your water, I am going to guess that the liquid algaecide you are using is a quat (quatenary ammonium). It is an effective algaecide but it can cause the water to get a little "sudsy" or "foamy". You may have had just a bit too much in there. A way the old service company guys would check your algaecide level was to put their hand in the pool and shake it around. If it foamed some, then you had enough. Usually a good shock will clear that up.