Spineless Cretons

Having installed a pond in my backyard and stocked it with goldfish, I've decided a little while ago that it would be an interesting experiment to see if I could replicate the clear water of the pond in the much larger pool. For some time now, the pool has been bright green, and quite uninviting to swimmers. This has been largely oweing to a deficiency of maintenance on my part and that of my housemates. Thus, if a small filter and a few fish can keep a little pond clean, then a big filter and a great number of fish should keep a much larger pond swimmable, completely sans chlorine. So far, this has not worked.
I have put in close to 30 goldfish and over 50 minnows (of which I know not how many survive since they are hard to count) with little noticeable affect on water clarity. As someone thuroughly trained in biology, it occurs to me that the water is still green because the fish only eat algae that is stuck to the side of the pool and not that which floats in the water column. Ergo, I need something that is a filter feeder. Now for the invertebrates!
I ordered cultures of freshwater sponges, copepods and daphnia (tiny crustaceans) and introduced them to the little pond. If they do well there, some will be transfered to the pool where they will hopefully improve water clarity. The problem however is that the invertebrates are so small that I can't see if any of them are even still alive in the pond now that I've introduced them. They could all be stuck in the filter for all that I know. Oh well. It is early yet and I suppose that after a few months, simply transfering water from one body of water to the other will be sufficient to introduce any of the invertebrates should they have survived that long.