stupid nitrates

I am trying to get my nitrates under control.  I did a 15 gal water change last night (tank is 90) and I tested it again today and it was STILL the same as before.  It is so high I am almost embarrassed to say, LOL!  It sits at 160 and it could be higher than that because thats all the higher my test will go.  I am using a API test kit.  I am unsure how old it is (if it matters at all?) because I got it with the tank I bought off of a couple. 
Last night I also cleaned out my sump and all my powerheads and repositioned them.  When I did this, I noticed a lot more crap coming up off the rocks and suspending into the water.  I checked the collection cup and my skimmer is working quite well the last 24 hours.  BUT the good news, the nitrites, ammonia, calcium and phosphate is good /DesktopModules/ActiveForums/themes/_default/emoticons/biggrin.gif  
Anyone have any ideas for me to try?

 

AZ-NO3

 

Do several 20 gallon water changes over the next 2 weeks and run Chemipure Elite.

 

Have someone else do a test for you. Might have a bad test kit as well. At 160 I would think your tank's inhabitants would be having issues.

 

I'd bet there fine, nitrates are the bi-product of nitrites and ammonia so i'd say if they are fine, your test is junk. Grab a new test kit, i wouldn't worry to much in the mean time.

 

I am gonna take it to aquatic environments today and see what they come up with. As far as fish reaction, they all act fine. I will post what AE comes up with.