New Sump and Protein skimmer

Yes, you'll want to match the salinity to that in your tank. I would fill the sump, start one pump, give it a few minutes and chack for leaks, then start the other one. Shouldn't matter what order--just easier to check each thing before starting something else up.

You'll want to get in the habit of checking the plumbing each day for a while--the new 120's didn't leak on startup, but developed one dripping area the second week of running.

And make sure and double check what will happen when the power goes out!!

All you need to do is drill a small hole in the hose just a bit under the surface of the water.
Then when the power goes off and a reverse siphon kicks in, the hole will break the siphon limiting the amount of water that dumps into your sump.

Some water will still dump so you need to make sure your sump has room. Do many, many tests on this one. Disasters of this nature are common yet easy to prevent if you just plan for the worst.

I definitely agree! I wouldn't use a pump--the problem is getting the return pump going at the same speed as the one pulling water out--something that's darned near impossible. A siphon break will work well--the new 120's pull less than 1/2 gallon out when the power goes off. The 65's will pull a bit more, but the overflow design is a bit different.

Sorry--those are my tanks. 120 gallon, 65 gallon.

Hey guys,
Just to clear something up here. CD, they are talking about drilling a hole in the return line and not the prefilter line.

Your tank should not overflow the sump as it will only drain enough water out to match the devider wall in the overflow box if you are using the external overflow. A good way to do this is to get your siphon box started and set the water level in the tank where you want it. Fill the sump up half way. Fill your protien skimmer up, turn it on and get it running and then turn it off so the water that will drain out of the skimmer will do so. At this point, you will have water in your siphon tube in the prefilter box but nothing coming down. You can now turn on your return pump to the tank and check your water level in both the tank and the sump. Your water level in the tank will rise about 1/2" so take that into concideration when you are setting the level of the overflow box. Check the sump to make sure that you have enough water in it so the pump has plenty of room to keep from cavitating. If there is plenty of room then you can turn the skimmer on and for the level again. To double check things, turn your pumps off and let the water drain down. If it starts to get high, check to make sure that your return line is not sucking water down to the sump.