When it comes to sw
bigger is always better. Get the largest tank you can afford. I had a 40 breeder for several years and even with a tank of that size things can go downhill very quickly.
However, I will say nano tanks can be very fun and rewarding but theyíre much less forgiving than a large sw
system. The only benefit with a smaller tank imo
is the fact that you can do large wcs much easier on a 20 gallon tank than a 150 gallon tank.