Oily surface wont quit!
Hey guys, I've been battling oil slicks on my tanks for some time now. I can soak it all up with paper towel and it's back within a day. I have increased surface agitation so much that it's splashing onto my lights and still- the oil is there. I have done 50% water changes. I have eliminated ferts for a bit, changed foods, took out all driftwood and rocks. Still- it returns! It's so thick I worry about oxygen exchange. I am considering a protein skimmer but really don't want to spend the $$. Plus, I have no idea how they work and dont have a sump or anything- these are small tanks- 20 and 30 gallons. What the heck can I do?? It's driving me nuts cause I think it's really unsightly on top of the concerns about fish and plant health. Started about 2 months ago and just wont quit.