The tank is coming along very nicely, plants and fish looking really healthy. I have nerite snails, they are great at tank cleaning and have great patterns, plus they are cheap to buy from LFS or eBay. Did you end up adding shrimp?
The tank is looking really healthy. Manado is a very light substrate, I have never siphoned it, well tried once and sucked up a load of it. All I do is wave my hand back and forth to stir up the detritus while holding the siphoning tube.