Hi, great site/forum and hope you guys can help me.
I have a saltwater tank that has been set-up for just over 10 or so Years. Its 4x1.6x1.6 foot with good size bio tank, I think it all holds about 250/280ltr.
I have 4 2000ltr ottos, one in the sump, 2 in the tank for flow and the last one in the sump, which go through a UV and then through 2 fluidised(?) beds and back into the sump.
The tank sit around 26 in winter to 27/28 in summer. Got about 18kgs of live rock. I change 50 liters about every 3 weeks. the last 4 months its only had 5 small fish, the largest being a wrasse of about 5 inches and they only get feed every 2 days(2 cubes of marine green and 1 brine or Krill cube).
All my fish have always come from the Gold Coast Seaway as with my fresh water unless I go outside on calm days.
The thing is when I've been doing my water tests the passed month the Nitrate is off the scale. I can change up to 100liters every 3 or 4 day till its all sweet and then in 3weeks off the scale again.
Now my question is this, is there a time frame, age limit to a Bio Tank?...
Should I pull the sump out and clean it out as if it was like new again?
Hope I've put enough info in and that someone can help.