Setting up a cheapo FO 29 gallon with damsels. I've got everything--but have a filter question (UG vs Canister)

[dascyllus58]

Hi, Setting up a cheapo FO 29 gallon with damsels. I've got everything--but have a filter question. I've got a UG filter but need to purchase a fair amount of substrate. I've got 20lbs of crushed coral but need more. Has anyone used mini marble chips (used for landscaping) as a UG substrate. Also, alternative is to use an old canister filter? Would that be better? And should I put bioballs or ceramic rings where the activated carbon would go (heard carbon is not good in marine tanks--removes trace elements or something). So I've got those 2 choices. I have an aquaclear HOB filter that I can use if I go UG. And please don't try to sell me on live rock--I'm not doing anything exotic here. This is a 1970s style fish only tank with ***** damsels. And maybe later on I'll invest in a skimmer. So what would I be better off with, UG or canister? And if canister, should I replace the carbon with bioballs or rings? Thanks.

 

[geridoc]

Forget the marble chips. Substrate carries out two functions - it serves as a residence for bacteria that lower the nutrient level of the water, and buffers the water to the proper pH (not alone, but it is part of the buffer system). Marble chips, round marbles, glass beads, etc. won't do either of these jobs. In fact, crushed coral sucks too, since many very personable fish like to burrow in the substrate, and will cut themselves on the coral; and dirt gets stuck in the crevasses of the relatively large pieces, and can lead to fouling your water. Don't bother with live sand, just get the cheapest sand your lfs has, rinse it and add it to the tank before you cycle the tank and it will be fine, and inexpensive. Along the same lines, don't bother with an UG filter - far too inefficient for marine use. When we used these filters in the 70's we also used large hob units, where most of the active biofiltration actually occurred. If you are determined to use only what you have, then go with the canister with ceramic rings (in marine tanks carbon is used only to remove medications or toxins when necessary - most of us don't filter with it on a regular basis) and a filter pad above to remove particulates. Be sure to regularly maintain the hob, or it will become a problem, and watch out for power outages, which can quickly turn your filter into a source of toxins. For fish only you won't really need a skimmer, just make regular water changes.