2rbps wont work though will it??
So your saying it wiill take up to 3 years to obtain its maximum size of around 12-13inches??
You'd need a much larger tank to obtain those sizes if ever. The largest Netterei I've ever had was 11" and it took 5 years. Nett's have a type of pecking order - they line up largest in the middle down to the smallest on the flanks. You could have 7 Nett's and none are exactly the same size. The largest could be 12" and the smallest ones could be 7-8" on the flanks for many years. And yes some Nett's don't get any bigger than that. You'll have better success at larger growth in larger volumes of water and like Bruner said - overfilter and waterchanges.