Do I need extra pump and why?

I have a 29g biocube. I have only ever used the pump that came with the tank. I went back in the posts on pumps and alot is said about what kind to get, but not about why have extra ones.
I have a few corals as you can see in my signiture list and they are doing good right now.
My question is should I be installing another pump and what would be the benefits if I did? Or shoud I stick with if it ain't broke don't fix it?

 

unless your having some issue, i wouldn't fix it. I keep an extra pump around but that's just in-case mine breaks, but for a 29g bc you could probably find some locally if that happened.

 

I think i called it the wrong thing, not a pump for the sump system... but one in the tank to move the water around more. The extra ones that attach magneticly that you put inside the tank, like a jet i guess.
Sorry still new and dont know all the termanoligy.

 

ahh, ok I normally call those powerheads (but i might be wrong). the reason for those is to provide extra circulation i the tank which has alot of benefits. it helps break keep the water parameters more consistent throughout the tank, so that the bottom of tank doesnt have alot lower Oxygen,etc. it keeps any bits of deterius from settling on corals, which helps keep them healthy and happy, and it brings more food to filter feeders , like your clam. there is probally alot more great things it does too. your corals might be doing good now, but if you add a small powerhead ill bet they do even better, and you will have less issues over the long term.

 

Most of the pumps in the bio cubes are not strong enough for the requirements of a reef system. You want at least 20x (580 gph) circulation in your tank. Also one pump usually leaves dead spots for detritus to build up and cause problems. If your tank is FO the installed pump is OK.

 

http://www.3reef.com/forums/reef-aquarium-articles-how-tos/basics-flow-78711.html