Adding a new sump help

[reefhead22]

I'm currently running a smaller sump under my 90g corner tank. I have plans to install a larger sump in my basement directly under the tank. My concerns are adding more water to the tank. Will I be ok to transfer my sump water out of old sump along with adding about 20 more gallons of fresh saltwater to my currently running DT?? What's my safest way of doing this? I would like to keep my sump downstairs so I can build onto my mixing station and eventually add on a frag setup. Last question is I have read about people getting some pretty good pull out of the mag. pumps. Would I have any issues using a mag18 pumping directly up to tank (about 10ft). Any input and thoughts would greatly be appreciated. Thanks

[examiner]

First question - transferring "old" water + adding 20g new? No problem at all. It's just a minor water change of sorts.

Second ? - http://www.reefcentral.com/index.php/head-loss-calculator

[reefhead22]

First question - transferring "old" water + adding 20g new? No problem at all. It's just a minor water change of sorts.

Second ? - http://www.reefcentral.com/index.php/head-loss-calculator

Thanks a lot for that link!! shows I should be at 718gph would that be enough for a 90g for a RP?

[greech]

Completely agree on the water change similarity.

700+ should be more than enough and may be too much depending on your total system water volume. How big is the sump going to be?

[reefhead22]

Looking at about a 30 to 40g sump (water volume) not tank size

[greech]

Ok so assuming 100 to 120 gallons of water after rock, sand and equipment displacement, you would be looking at 400 to 600 gph as the range to be in. The 18 will handle that from what the calculator indicates and may need to throttle it back with a valve. Make sure you account for bends in the pipe when calculating head loss.

[reefhead22]

Yes sir I added those in. just a 90 bend and a 45.. maybe ill just use two 90 bends