SW filtration Q's

[invadertoast]

I went to the local Science Center today where they have several salt water tanks set up. There are a four large ones with stripers, lobsters, hake, skates, and other local (north Atlantic) species. There are also a few smaller tanks (ranging from 50-75 g maybe) and a couple were using under gravel filters along with a HOB. Does that make any sense? I don't know much about salt water but it seemed strange to me. Just curious about how it works, I've been in there several times throughout the year and they always have the same fish in the tanks (seahorses in one) so something must be working.

[ILuvMyGoldBarb]

Well, the since you are dealing with cold water SW tanks it is a bit different. Obviously, they can't use tropical live rock as it would not be natural for their environment, however it is still possible to use natural filtration, it is just a bit more difficult to do. Coldwater marine tanks are notoriously difficult for a reason, the biofiltration comes almost entirely from the sandbed and some porous rock. HOB filters and UGF filters can be used, but I would bet they are doing a lot of maintanence on those tanks all the time to maintain them, especially the seahorse tank as temperate seahorses are very difficult to keep.

[invadertoast]

Thanks! I know tropical SW tanks use live rock but I wasn't sure if it worked the same for a cold water environment. They must do alot of maintenance because the tanks are always really clean and the inhabitants are always healthy. On the other hand, they have one freshwater tank with local speices (sunfish of some sort, turtles, and catfish) and everything looks like it has finrot and has looked that way for 6+ months.

[ILuvMyGoldBarb]

That filtration is basically the same in a coldwater marine tank, it is still entirely done by aerobic and anaerobic bacteria, just the medium for housing that bacteria is slightly different in appearance, it's not the typical live rock that you would think of.