This is off topic but you really need to start buying equipment online.
Ahhh... so I'm not the only one that thought $2000 for lighting was a bit excessive?!
If you're spot feeding of that sun coral is excessive, that will probably foul the water quickly. I think you saw MsBeanCtr's post about spot feeding with a cut up 2-liter pop bottle as a "food concentrator" so if you're not doing that, you might start to minimize the waste food.
I think the twice daily feeding and all the spot feeding probably slowly got you to where you're at now. It's not going to go away quickly, but the Phosphate reactor will help, reduced feeding, and more frequent water changes for a while - maybe 15% twice a week? You're most likely not reading any nitrates and phosphates because the algae is sucking it up as food as quick as it can be created. Your lighting period doesn't seem excessive.
After making sure your source water is pure, I'd do the things noted above and keep manually pulling it out when you can. Over several months you should tell if you're winning the battle. You could do a "lights out" for several days, but I don't know how the clam would like that - I have no experience with those. Maybe someone else can comment on that.