Need some help with new tank

So I just bought my first tank. It's a cadlights versa 42g. Anyways I love the tank and the look. But I can't figure a couple things out. First off with my return pump, it seems to work fine and move water like it's supposed to but the second I completely submerge the flow head the flow slows way down. I'm not sure what's causing this???? The second thing is I hard plumbed the tank and had a question on the height of the return drain. They recommend setting it up "durso" which I did I'm just not sure how high or low I need to put the actual drain opening in comparison to the overflow level. I'm probably not asking these questions correctly but if anyone understands my newbie jibberish please help.

When I bought my Cadlights, all the plumbing was included. Did you use your own plumbing? If not, all the pieces should be cut to the exact sizes.

I bet if you posted some images someone would be able to help.

Your return losing pressure is odd. The flow will naturally feel a lot slower underwater. How far underwater are you placing the return nozzle? It doesn't need to go super low because of back siphoning issues- unless you have a check valve.

Marcos

Thanks everyone, So i think i figured the plumbing out as far as the Durso setup and it's sounding and draining much better. 

So the more turns the water has to do to get back to the tank it will slow the flow. Mine is plumbed with the return right below so oppsite yours. We also stepped up the size of the pipe. I'll get you a pic of mine hang on. I never tried using the pump it came with I used my DCT 8000 because it lets me choose the speed and we made it so I can have it almost all the way turned up which in turn makes it so I don't have to use a power head in my display.

Ya, and that makes total sense, The only reason i did it this way is because that's what it showed in the picture. Those directions were terrible with the cabinet. So i have no idea why i even looked at how they had it set up . I'm guessing i will want to replace the pump anyways because i want dual heads on mine just like you have yours. Where can i buy that dual head? and is it 1/2 inch?

It was eBay I got mine off here's the link, you can get them with the flat nozzles on the end too just search eBay
http://www.ebay.com/itm/1-2-DUAL-NOZZLE-AQUARIUM-LOC-LINE-READY-FOR-AQUARIUM-USE-OR-SUMP-FREE-SHIP-/111720240637?hash=item1a030b95fd:g:CO0AAOSwPgxVOTDg

Here is the pump I am using but you will have to modify plumbing to receive more pressure
http://www.amazon.com/Jebao-Jecod-Marine-Controllable-Water/dp/B00SQX5CCO

DMower wrote: Get that metal clamp out of your tank. Use plastic.

Good catch I didn't see he had that on there! I can't ever find plastic ones so we used zip ties:)

So here is what i did, And it honestly didn't change the flow much. And i'm pulling the Stainless Steel clamp right now. 

bstuver wrote: It was eBay I got mine off here's the link, you can get them with the flat nozzles on the end too just search eBay http://www.ebay.com/itm/1-2-DUAL-NOZZLE-AQUARIUM-LOC-LINE-READY-FOR-AQUARIUM-USE-OR-SUMP-FREE-SHIP-/111720240637?hash=item1a030b95fd:g:CO0AAOSwPgxVOTDg