clam only tank

[Rikko]

The shallower the better, obviously, considered how light greedy tridacnids are. 30 isn't bad - personally I think if you went ultra shallow like a 15 gallon it would start to look goofy, so you're probably on the right track there.

I've read several accounts of people plumbing their clam tanks into their main systems, which benefits both. The clams now have a good food source in all of the dissolved wastes in the system, and the system itself is kept cleaner as a result. The only obvious downfall can be if "something happens" and the system crashes.

If you just plumb it in to your main system, there's no cycle to speak of. Any dissolves wastes in the water get flushes out while bacteria are growing in there, so there aren't any problems (analogous to doing a 100% water change twice a day - essentially you bypass the cycle).

As for how long.. I would probably leave it up and running for a week or two just so you can observe flow patterns/lighting and make sure it's all cozy and stable.. If that's set, your clam tank is essentially just your main display anyways, so let the system as a whole be your guide.