problem with pump flow

What size lines do you have on the drains and returns?

Do you have any pictures, the 1" drain and return is fine.  I had the same problem a little while back with a FW set up, these guys/gals here told me not put any valves on the drain, I agree because if by chance you get something in there it might block it off enough to cause an overflow.  Two days later a fish got stuck - no flood because I have a backup drain.  Anyways everyone must be having dinner or something I would post a few pictures, I will do my best to try to help you out, but I am sure some others will chime in. 

wouldn't it be as simple as adding a larger overflow?

you are restricted by the diameter of the U-tube.

gottcha, sorry bout that, should have asked.

I would say as JSTDV8 said that it is not draining enough, I had the same problem with the clear tubing I used for the drain.  The stuff I have kinks really easy and restricts the flow.  I think your LFS was right about changing your drain to pvc pipe - however there is drain tubing you can buy that doesn't kink so easy (what I am trying to say is it looks squished not perfectly round), 2Quils and acrylics PM'd me a site with the hose to use, I will PM you. Might be easier than hard piping it.

Sorry - are you sure there is nothing blocking the drain - maybe a snail of something.  The drain hose you have should be fine as long as there are no kinks in it.  I also think that your 1" return might be a bit large that's if why it is taking a lot to back it down with your ball valve.  I wish 2Quils or acrylics would chime in, or someone. 

You say your using vinyl tubing???? Is it the clear tubing that you can see into....I would visual inspect as you probably already have and others have suggest, but I'd be looking around the bulkhead....Without seeing pics and you said the tank was drilled....Is it a reef ready tank or did you drill the tank  yourself?  Where exactly is the bulkhead located?  I would actually start probing around in the bulkhead....You'd be highly suprised what you think/thought couldn't make it into the overflow into the drain will.....I would almost bet that something has gotten into the bulkhead and assuming you have some sort of elbow or sort coming off the bulkhead if drilled in the back of the tank, and snail have a tendency to hang up and stick right at the back where you really can't see them till you start probing around.....

 

If there are no kinks or sharp bends in the line, then the clog has to be within the bulkhead itself. 

Do you have a valve on the suction side of the pump or the output side of the pump?  Is it possible as well that your ball valve might be hanging opening and not really closing off as you think by indication of the handle?

So I'm alittle confused.... Is the drain slow or water from the Mag slow? You said you have a "Y" on your return side of the pump, how is the flow on the other port of the "Y"? Have you checked the pump itself?? Meaning pull the head or housing off the front of the pump and inspect the impeller?

If the return flow is super slow right now and you're having problems with the tank not draining fast enough there must surely be a blockage in your drain lines somewhere I would think.  I would take the drain apart and inspect.

It’s obviously in your drain system. Start by making sure the ribs of your overflow box are clean and you have no buildup of algae that are raising the height of the water needed to dump into the box

You might want to use one of these periodically...Even though you have a drilled tank, algae and debris can grow in your tubes......I do not have a drilled tank, BUT use this on my overflow tubing to keep them free and clear....

 

 

Oh lois you tempt me so

Hey JAXFishGirl how are you making out with the flow problem?