Re: Fluval
JC, I use a Fluval 4 with my hatchling tank and it has been suitable for that application. I use the duo-density replaceable filters which includes a layer of carbon. I also put carbon particles in the central tubular member. I mount mine horizontal in the tub because the water level is a ways below the top of the tub. It always keeps the water crystal clear. Also, I like very much the flow control knob so that my hatchlings won’t become projectiles when they get on the output side of the filter. I wouldn’t suggest Fluval 1, 2, or 3 for turtles because of the high waste of turtles but a Fluval 4 should be okay for, at least, hatchlings. The downside of the Fluval 4 is that the filter needs weekly cleaning/replacement – preferably replacement. If the filter isn’t changed the water flow drops to nothing. Noise is unpredictable – some run routinely quiet and some run routinely noisy and I haven’t figured out what this is caused by. Just cleaning the filter will not yield optimum flow. A complete replacement of the filter is needed to get back to optimum flow. If you have anything other than hatchlings I think I would suggest a canister filter. I use an Eheim professional cannister filter with my 2 year olds and it can handle lots of waste without needing frequent filter changes and it runs real quiet. Bob