how often are you changing your water, i can go all day but i know you said you went to long without a skimmer but joe i have a beautiful tank with no skimmer on it and my stuff grows crazy, only algea is a little bit of bubble, but my emeralds take care of that just fine, second is your light led?, third do you have any sand sifting fish, wrasses in general, snails, stars, cucumbers? forth do you have a sump and whats your flow rate to your whole system you may not be slow enough through your sump for nutrient fall out if you have a fuge. i had this problem in a 210 fish only tank it took me six months to fix it but i got it by gravel siphoning a tlf phosban reactor and rearanging rock, i manually started by moving 1/3 of rock every month and a half until i fully gravel siphoned and restacked rock so it wasnt like a rock wall in the aquarium, and the reason for it getting so bad was i didnt do proper water changes on my system and i just took risk after risk i know i was messing with fire the tank was set up for 8 years and boom started gravel siphoning and it took time but i got it fixed and now that you have not a whole lot in your system and trying everything it sounds like starting with a blank canves is what you need most perameters are in check. on my 180 i did 30 gal changes every week and changed my filter sock everytime my skimmer never skimmed lol wasnt that good, i was unable to do gravel siphons tank was to packed and it was up within 6 months packed full but had 200 nassarius snails 3 wrasses and a few cucumbers and sand sifting stars.