Urgent Return not working!

I hope someone can help me. I have a 210g tank. Has two built-in overflows that are full to the top w/water but last section in sump only has about 4 inches of water which is stressing the pump with so much air being pulled in. One pipe that dumps from the overflow to the sump is not working. My husband is out of town so I cannot take the hood off of the tank to see inside the overflow. If I add more water to the sump, it overfills the tank and runs over the top of the tank.....while the sump water (in the last section) stays low. Is there anything I can do until he gets home late tomorrow? Don't want to burn up the pump. Please help!
Thank you,
Kas

 

Is there a ball valve in line after the pump that you could throttle back? That will lower the tank level and raise the sump level.

 

Yes! Tried that and it worked! I closed the ball valve until the sump got to an acceptable level, then opened it up just enough to maintain. Water is now moving very slowly through the system................will that harm the pump with so little water moving through it?

 

It'll be fine so long as its not completely shut off. If you can take a piece of tape and mark the water level where you want it in the sump then make small adjustments on the ball valve until that level is maintained a few minutes. You should be good to go.

 

This puts stress on the pump. What you need to do is split your return. Have the tubing go up to the tank as you normally would, but have another hose attached to the 'T' that has a ball valve on it. Open or close the ball valve as needed. This will change the amount of water reaching the tank and not put back pressure on the pump.

 

Agreed but you should be fine until your husband returns.

 

Thank you SO MUCH for your help! One more question please: when my husband returns home tomorrow and we're able to get the hood off of the tank so I can look inside of the overflows, what do you suggest I try first to fix this problem? The water in both overflows is even with the tank water level. I thought water was only supposed to run down the sides of the overflows and not fill them up.

 

More then likely you have a clog somewhere once you get the hood off you should be able to spot any problems pretty easy and take care of it from there. Are all your fish and coral accounted for? Maybe something in the tank went over the falls and is partially blocking the overflows.

 

Yes, I THINK all fish are accounted for and all 5 urchins are in tank. Thanks again for all of your help. I can't tell you how much it's appreciated. I think I need to move back to the 75g tank. It's small enough for me to handle alone.
Thanks again!
Kas

 

What he said. ^^ I agree you most likely have a clog in your lines.