What is your current/planned stocking list?
If it's what we've discussed before, I don't think that syno cats are a good choice; your gobies and shellies will scavange quite a bit, and if you need further cleanup you are feeding too much. Synos will disturb the breeding of all your species. I keep a group of S. multipunctatus but they've got a dedicated 55 gallon tank now. My calvus never bred and my julies had zero fry survival when they all were in the same tank.
If you want an algae eater, I recommend a bristlenose pleco (Ancistrus spp.).