Saltwater tank filter?

i have a 36 gallon bowfront with two hob filters i change the sponges weekly and have 40 pounds of live rock in there with four fish....ment to have three but live aquaria made a mistake and gave me two -_- i meen i dont mind. n idk how to get it out my friend wants it.... ok so as i was saying..(sorry) i have an aqua clear 50 and a bio wheel 20 (filters) i get a lot of brown algae but thats bc of phosate i am guessing bc of my fish food but i underfeed and wash it before i put it in. and cleanin the tank once a week will be good do a 10% water change but always over due our filtration i say i also have a hob skimmer i am not sure that'll be necessary for yoursi do about a 5% water change everyweek which is pretty good for a 36 gallon tank. and a clown fish might not be so good in a 12 gallon saltwater tank they get pretty big i have one in my tank as well with (2)dracula goby's and a red scooter dragonet ohhh and also i have a bunch of snails and two shrimp thats formed a symbionic relationship with both gobys which is pretty cool. but yeah get more then just a sponge filter my filter has 3 stage filtration i get absolutely no green alage and my purple corraline algae is growing like crazy its so hard to scrap that crap off my front glass bc of the bowfront lol i have to do it everyday bc of how fast it grows i also have four corals frags in there xenia coral, starburst polyps, eagleeye polpys, and 1 duncan they are growing pretty fast too iv had them in there for about 3 months not everything is turning out veryy nice just the brown algae i want gone so i might have to buy some kind of phospate remover...or try to capture the little dracula goby and give it to my friend lolll. omg i am sorry for this huge message i love fish i wanna become a marine biologist loll i also have a rele good light its an led marineland 10,000k 1watt light its amazinggggg how it works my corals love it i rated it 5 stars and would recommend getting it if you wre looking for corals 12 gallon would be amazing for some coral frags in there its really not difficult to care for corals after the 1st month of them being in there they grow pretty fast well mine do bc there polpys stony corals take longer like acropora. your tank should do fine just do a better filter then just sponge. sorry again for talking to much..lmao bye.