First, they are beautiful. I have had mine for about 4 years now. You need to make a few changes. One remove the filter socks or floss they often catch tons of pods and then you throw them out. Next, you have to feed your pods Phyto and they will multiply in your tank. I feed my 150G tank every other day. On the plus side you are also feeding your corals. I do introduce pods and rotifers avery 3 months just for diversity. You can never have too much as the levels adjust themselves based on the available food. By the way amphipods are a great part of your cleanup crew and act as food for other fish that you may have. Good luck, stay patient, in a 150G tank it is common for them to disappear for a day or two as there is food everywhere.