MLT Problems - draining very slowly

I built a MLT out of a cooler with the instructions on the forum, and the first 5-6 batches I made turned out great. When I opened the spigot, the MLT drained right into the pot.

The last few batches I've tried, the flow of wort out of the spigot has been very slow, just a trickle, and I think its getting worse each batch.

Is there some maintenace that needs to be done ?

I was thinking of cutting a couple inches off my stainless steel braid and reattaching it because the briad is sort of worn out near where it clamps to the hardware.

Not only is it slower than it used to be, I think my efficiency is not as good as it once was, though I'm not sure what that would have to do with the MLT draining slowly.

Maybe its clogging up. Try blowing back into the tubing. That should blow the stuff out, if theres anything stuck...

Maybe your sparging too quickly and getting a stuck mash. Your grain bed maybe compacting and slowing your runoff. That could also be the answer to the inefficiency as well if your getting channels through your grain bed.

Well I took the hardware apart and cleaned it and put it back together, and I didn't see anything clogging it. After reviewing my notes I noticed that my grain bills are getting larger and larger over the same period that my mashing has been getting slower and slower.

I bought ingredients to do a small 4% Common Bitter, and I'm suspecting that I'll have an easier time mashing 7.5 #s instead of 11 #s.

Also, I saw something really cool at the Home Brew Store tonight - they have a stiff mesh screen / tube that would be perfect to replace the stainless steel brain in my MLT. This thing is stiff enough that you could put a lot of grain in there and it won't compact flat, and inhibit the drainage which is what I'm strongly suspecting is causing the problem.

I think I'm going to have to invest in one of these and make a bigger MLT.