That's pretty young to have so many so I'm guessing you've been active in that beautiful Southern California weather for awhile.  I'm very active in all sorts of outdoor sports too so here's what I do for optimal sun protection.  I layer ........and here's how:

1.  After washing, 1st layer is with Mexoryl 3% like the SkinCeuticals Active SPF 15. Remember the SPF doesn't matter much as long as it's 30 or over- all sunscreens cover UVB well  so it's the UVA and other qualities of the sunscreen you care about;

2.  2nd layer - if not sweating, Dermaquest ZinClear SPF 30 (18% zinc) - but it's not chalky.  Or, if sweating the SkinCeuticals, SPF 45 Sport;

3.   3rd and last layer, Colorscience Sunforgettable Powder - with the brush and slightly tinted. 

If you layer all 3 of those and then just reapply the powder at the turn or on a tennis break if sweating alot, you will be maximally covered.  I've done short triatholons with this, and the layering really works and it wears well even in the water or with sweating profusely. 

Our office # is 206 - 215- 6600 if you need to get a personal message to me.    Dr. I