It can be a viscous circle. Corals start to fade and die Nitrites and Ammonia rises more Corals die, can't change water fast enough. Fish become stressed get sick even die. From what you have post I can only pick out say three things to look at seriously. a.) Lighting 95 Watt strip is not going to do it, softies or not. I highly recommend looking into some better lighting, even in their on site it states for Fresh or Marine and have a drawing of circled of Fresh and Marine Fish no Corals. Those lights are just for your enjoyment to see the fish and any artificial Corals or Plants that you may add, which they nicely have advertised right below the Tanks. b.) In tank Flow meaning if you shut off return pump how much water would be flowing in the display, you say 3 power heads but no info on their out put ratings. Corals depend greatly on flow to feed them and to stripe away and detritus and mucus. It's not the speed so much as the mass/volume of water. Do you feed the Corals at all? Acropower is great because of the Amino Acids.
c.) You mentioned 1 ppm out from RO/DI if that is so how long has this been for could it be around when you started to have problems, one of the first things that DI resign starts to release is Ammonia when resign is exhausted and it does not show on TDS meter, so in reality you could be adding double, triple or more into your make up water. Change the resign and change it before the color has totally change if you use that type, about when it still shows about 1/4 left. I just added this video for you as I found it very interesting.
Good luck and don't give up, you are almost there.