Hi,
Tube Sizes ?
F40T8 are 60"
F32T8 are 48" -- the common one.
F25T8 are 36"
F17T8 are 24"
But...
F40T12 are 48"
F30T12 are 36"
Confusing eh ? 6500K is commonly available for F32T8s (GE, Sylvania and etc). Other "aquarium" colours are avaliable from Zoomed and Hagen.
Why not VHO ?
Problem...if I use 110W for VHO and get the same intensity with 80W OVRNO, I would rather use the OVRNO (environmentally friendly). Where does the extra power go....heat. Plus...VHO tubes are not $3.50 CAD....more like $30--$40. Also, VHO tubes are fatter...harder to control the lighting. But...again it is a lower risk lighitng solution.
Okay...the $60 VHO ballast. I looked it up and they are magnetic...lower effiency and low ballast factor (i.e. VHOs are designed to accept 110W of light power from the ballast...but the ballast delivers something lower. Typically a ballast factor of 0.85 is typical. So, the VHO ballast would only deliver 94W to your 110W VHO). If I wanted VHO...I would just get a setup from Hellolights (less hassle). Good point...just...I am having more fun with this OVRNO...
RFI (RF interference):
Hmm...gotta check it out. Most of appliances (TV, radio and such) are working as they usually do. Maybe, I need to place it near the reef for it to disturb it. Depending on the ballast design, RFI can be a problem..or not. However...if you shield it properly (ie place a metal foil or tube around the RF emitter -- which are usually the wires between the ballast and the tubes), then you should stop most of the RFI. Excelent point.....
I hope I am not shoving this down people's throat
I have heard of many people asking if it is possible to overdrive NO without a Icecap. I am just posting in response. Personally, I enjoying doing stuff like this. I could always go out to the LFS and buy an Icecap ... but I think this is more fun.
Hope that helps.
- Victor.