Hi everyone!\n\nHere's what is going on. I adopted a 45 gallon marine tank from my brother. It's pretty old. Maybe 15-20 years old. Here's what I took from what he had:\n\nLive Rock (although apparently not enough live rock for the size of the tank)\nSome existing sand (maybe 1 cup?\n5-10 gallons of his original water to keep the rocks alive in transport\nsump (might be just 7 gallons, so not very big)\npump (I'm not sure of its specs) with return hose\noverflow box with pre-filter -\- but it was so old and brittle it fell apart, so I replaced it\nbio balls -\-I've rinsed these out, and put back 3/4 since I'm phasing them out slowly. I'm hoping to set up a refugium later on\nsalinity tester\nlighting\n\nHere's what I bought and are in use/in the tank:\nAPI saltwater test kit\n1 pre-cured live rock from a reputable aquarium store\n10 hermit crabs and 10 snails for starters\na bag of live sand\nCrystal Sea salt (not sure of the name...bag's downstairs)\na penguin power head, just to keep the water flow going in the lower part of the tank -\- safety basket around it to keep fish from getting sucked\nPurigen in the trickle part of my sump to help with the nitrates\n\nI also bought, but haven't hooked up:\nused Berlin Red Sea skimmer-\-I still need to buy hoses since it didn't come with any\nRio pump, new, that they said will work great for my needs\n\nOK. I'm familiar with an aquarium's cycle, since I have experience with freshwater tanks.I have not put any fish in there because... I am at a total loss at why my nitrates are at 160+ppm!!! I've never had that sort of problem. My ammonia and nitrites are 0PPM and holding steady there. I've been doing 10-20% water changes for the past 4 days, and I would have thought that at LEAST the levels would go down even just a little...but it doesn't seem to be helping. I know it will take a while, but seriously...it hasn't gone down at ALL. Now, I did check the saltwater before I put it in my tank, and I detected maybe 20ppm of nitrates already (straight from the tap, and I treated it with Prime for the ammonia, chloramine, and chlorine). Could that amount be causing my difficulty in lowering my tank's nitrate levels? I didn't think nitrates would be THAT HIGH during the cycle process. \n\nI'd like some insight on this. My brother had stopped really caring for the tank a year ago after losing his last fish to ich. He just maintained the water levels and salinity, but nothing else. I rinsed out the sump, rinsed the live rock a little in salt water to shake off some of the bad growth, I've rinsed out the filter sponge in the sump. What could it be?