MH bulb orientation question

[Bob I]

Originally Posted by Canadian Man

Because you use Aqua Clear hang on filters on your tank and they create current back to front rather than the typical side to side that most people have?

did I get the answer correct?

If it were only that simple. I don't use Aquaclear filters. My surface agitation is caused by Fluval returns both pointed the same way. The ripple effect is still stronger with the bulb oriented parallel. The pendants are the same. Therefore the only physical difference is the way the pendants are nounted. I am curious why perpendicular mounting is recommended.