What is doing your biological filtration? Two pounds of live rock isn't doing anything. Is their LR or some biological filter media in a filter or in the refugium or something?
If your double flourescent light strip is a standard freshwater double striplight, those bulbs need to be replaced at least every 6 months. Based on when you set up the tank, they are due to be changed.
I don't want to sound harsh, but the tank isn't set up properly nor do you maintain it properly. Mysis should not sit in the tank all day until you siphon out the "gross leftovers" at night.
Seahorses should be fed what they can eat in one feeding only. Not overfed so mysis remains after they've had their fill. Just because you're not home to feed properly isn't a reason to overfeed the mysis.
I know you've done lots of research about seahorses. I know you didn't have luck with them the first time around. However, I think part of the problem is you cannot be successful keeping seahorses if you only have 5 minutes a day to quickly feed them a bunch of mysis once a day and maintain the tank when you have time.
A seahorse tank is not like some fishtanks that you can ignore alittle with no consequences. Seahorses tanks are generally lower flow, and since seahorses are such messy eaters of high-protein foods algae problems can arise quickly if you don't have the proper setup or time to care for the tank.
While I think a lot of the problem is the tank just isn't mature yet, I think a large part of that is because the tank isn't set up properly in the first place. You have basically no live rock, high phosphates, overfeed the tank, older lightbulbs.... etc.
The good news is the issues can be corrected. In your instance ozone is NOT the answer. IMO you need to purchase some more LR and get the tank set up properly. You also need to free up a bit of time in your daily schedule. I know how hectic life can be and how precious free time is - but you need to find a bit more "seahorse time" in your daily schedule.
Tom