YUP you have monster flow !!! That's allot of gph your pushing there.Flows very important but it's easy to get carried away.That's right I actually said that. I also have a closed loop and had the multiple tunze's going as you do.To the point I had to epoxy stuff down or it was going surfing.I read Anthony Calfo's book and it really changed my opinon and what I thought I new from reading fourms and talking to any fish geek I could listen too.If your only running at 30 % you should reavaluate what your flow plan is.I ditched the tunzes(actually gave them away) and went for a wider less aggressive flow(vortech mp 40) I know look for detrius suspension and dead spots.As long as the water is passing over the corals they are getting fed and absobing nutrients. I tested my tank for flow with a kent target feeder and watched what the phyto plankton was doing.If it satyed in place I adjusted accordingly tell I got movement in all the places I tested. I was able to replace 2 korilla 4's and 4- 6125 uni balls with just two Mp40's and a MP10 that creates bottom flow accross the sand bed,with the wireless controlers I have more flow options then ever.I am now even considering unplugging the closed loop,seems like a waste of money.I noticed considerable polyp extension and have enjoyed better growth since getting off the sunami wagon.You should see how fuzzy the pink birdsnest you gave me is !!Just my .02 tho Tom. Maybee you should try one tunze on each end see if you notice a change with a concentration on dead spots.I would be intrested if you get the same results.Good luck