Nitrate issues

It sounds like most of your issues are coming from the bio balls they tend to be nitrate factories.

 

Bio balls are a joke, I was told to stay away from em!
Did I read this right? You have 250 lbs or LR in your 90 gallon? Wowzers, can the fish even swim? lol

 

My guess is the bio balls and filter pads are your problem. I don't know anyone that uses either one of those for saltwater.

 

I would disconnect your sump, drain and clean the whole thing, ditch the balls and pads, then set it back up with new salt water in it. You could also use some of your DT rocks and put them in the sump if you want to thin out your rock pile.

 

Honestly, I don't even know what pads you are talking about....I just know filter pads in general tend to soak up the crap in your tank.

Filter socks, on the other hand, I run those. They work great but you have to switch them out every few days or they too become nitrate factories.

As for pods, with all your live rock you most certainly have infinitly more pods in your DT rockwork than your 20 gallon sump. I wouldn't worry about it.

 

GL mang

 

They do make bioballs with all kinds of things inside the ball that act as well or some say better than actual live rock because its more porous. If you have lots of flow pointed at the bioballs occasionally so debris is not building up on/in them, they can work fine.   Some people place them in a mesh bag so they can be rinsed off occasionally.  Basically anything that can collect a bunch of debris/gunk can become a "nitrate factory", filter socks, poorly circulated sump etc. Might want to try kicking up the flow around the bioballs first, add a filter sock or 2 etc before you scrap it all /DesktopModules/ActiveForums/themes/_default//emoticons/smile.gif

 

Thats a big water change!
here is the main points from a "lower your nitrates" write up by Melev

If your tank is suffering from high nitrate levels, the success of your reef will depend on your being able to get this under control. Changing 100% of the water would be the ideal, but it may shock your corals, fish and invertebrates in the process. A more gradual way is recommended.

Example from my 55-gallon Reef : Make up 20 gallons of fresh saltwater in a trashcan in front of your tank. Drain 10 gallons of tank water into the 20 gallons of new water, and let that mix. Pump 10 gallons of that water back into your tank, and let the power heads mix that water up in your tank for a minute or so. Then repeat this three more times. Dispose of the now polluted 20 gallons of water. Make up another 20 gallons of fresh saltwater, and repeat this procedure. As long as your temperature and salinity match the tank, your inhabitants won’t be affected adversely, and with each rotation of water, the nitrates are being diluted and removed from your tank.

Simply pulling out all of the water in one massive water change puts stress on your entire tank. Doing small water changes consistently won’t bring nitrate levels down. At best, it will maintain them at their current levels. Using the example above, a tank that was at 80ppm would be around 30ppm after a couple of hours work and your population will be happy and unaffected. Once your nitrate levels drop, they are easily kept low with regular water changes, as well as the use of a DSB and macro algae.