help with flow rates

[Jimbob_1978]

Hi guys and girls i`m just starting out in the hobby and have a few questions. I`ve started to set up a 20g reef, how good does the circulation have to be and is it possible to create too strong a current? I`ve added all the live rock and some corals etc and i`ve recently added 2 common clowns which seem to be struggling against the current. I have 2 power heads at either end of the tank pushing out 5g / min, how should i position them?

 

[Anonymous]

Welcome to reefs.org, Jim_Bob. General rule of thumb for reef is turnover (that's through the filtration) on the order of 10x the tank volume/hour. However, with a nano it's gonna be really easy to get "the toilet bowl effect". Clearly, if they're having that much trouble you need to ramp that turbulence/flow down a bit.

Also, in my opinion (just bein' truthful with ya here), those clowns will get too big too quickly for that size tank. I'll suggest you reconsider (and I'm also really, really hoping that you quarantine EVERYTHING for a minimum of 30 days) for something instead like neon gobies, the smaller wrasses--such as six-line or smaller fairies, instead.

 

[Jimbob_1978]

thanx seamaiden