Rebuilding old sump-Need advice!

[Dundermifflin]

Running a 110 gallon tall FO. The original set up was built in 2005 and was shut down for a couple of years. (Pictures attached). Just updating everything and getting it back up and running now. Started cycling the tank two days ago. Looking for advice on how to properly setup my sump as I'm learning bio balls are a thing of the past. I was going to replace the bio balls with dry rock as suggested from another post and let it cycle through before adding fish. Anything else needed in the sump other than a couple dry rocks and the protein skimmer? Should I use any media to remove debris? How long should the rocks cure/cycle before adding fish?

I also have bio balls in the overflow box at the center of my tank. Any suggestions on whether to leave those or replace them with something.

Thanks.

[thegrun]

If it were my sump I would make some extensive modifications. Yes all the bio-balls should be removed from your system. The problem (to me) is that your sump was designed as an old trickle down design. The problem with the old trickle design is that while it is very efficient at converting ammonia to nitrates, they do produce a lot of nitrates which in turn feeds algae. The other problem is that as designed the skimmer is not going to produce a consistent skimmate since the water level the skimmer sits in will fluctuate. I would close off the slot at the bottom of the sump and cut down the divider between the two sections so the water flows over the top of the divider, not under it. This will allow you to place the skimmer in the first section up on a platform so the skimmer sits in the correct water depth. The return pump would sit in the other chamber and the water in that chamber will fluctuate as water evaporates from your system. I personally would add a filter sock in the first chamber also, but only use a filter sock if you are willing to clean it every 3-4 days or it also will add to your system's nitrates. If you don't want to clean the filter sock regularly then go without any mechanical filtration at all. Do not add any fish until the cycle is complete, which usually takes 4-5 weeks, depending upon your live rock and what you use as an ammonia source. The tank looks beautiful, keep us posted with your progress.

[Dundermifflin]

Thanks for the feedback. Would you also suggest removing the bio balls from the overflow box as well. My LFS suggested putting PVC back there using a 1" pvc pipe with a T towards the top and a cap with a hole at the top of the T and a 90 degree elbow at the middle of the T for the water to go through. Or is a better to make a standard standpipe that just goes straight up with no T and elbow and just drill a bunch of small holes in it?

[thegrun]

Yes I would also remove the bio-balls from the overflow box. I like the tee and 90 elbow facing down and a small hole in the end cap setup. It is also a very good idea to have a second drain line as an emergency drain line. The second drain allows you to install a gate valve near the end of the primary drain so you can slow down the flow so that the water backs up just to the overflow box, this will allow you system to drain silently. Never use a valve in your drain line if you don't have a second emergency drain set so the intake is just slightly higher than the primary drain.

[Dundermifflin]

So if I do the T and 90 degree elbow (researching and it looks like that's called a Durso Standpipe)-how high should the intake at the bottom of the elbow be inside the overflow box?