Flow rate and need of powerhead?

[DWhatley]

The Koralia magnets are very strong and where I use them I have not had an octo relocation problem. However, I mostly use the stand only and wedge the unit in the live rock.

 

[Pennyworth]

My powerheads will be situated on the glass, hoping the magnets are indeed strong enough..so far they have survived starfish and large snails hanging off them. Is there any need to secure the powercord it is attached to? I have one running across the tank, and don't want the octopus to pull it and maybe pull out a cord or something...

 

[DWhatley]

The magnets work very well and you should not have an issue (this assumes a Koralia, but I think most brands have strong magnets). Cords are a PITA in general but the only thing I have had as a problem is pencil urchins chewing on them (a likely cause of some of the electrical shorts you will see mentioned in reef forums). Koralias used to come with a funny spiral wrap with no clear usage. It is used to put around the part of the cord that is in the water for this purpose. I am not sure if they still provide it and most people don't have issues. Keeping the cord free of algae will help with the clean up crew potential problems but I have never had an octopus interfere with the cord.