Dual Durso not draining as well as it used to

[bureau13]

My 240 gallon tank has a built-in overflow with dual Dursos for the drain. I've always had to throttle back my Super Dart to match the drains, but not a huge amount. Also, previously if I blocked the air holes at the top of the pipe it would start to siphon and drain much faster. Lately, however, I noticed my display tank water level was way too high, and the water level in the overflow is at the same level. I had to throttle the return pump back significantly farther to not overflow, but while I'm getting water from the drains, it's not just trickling, I can't get it to drain fast enough to reduce the water level beneath that of the display, and plugging the air vent holes seems to have no impact. Any idea what's going on? Surely if one of them got clogged, the other one could still go into siphon mode....I'm at a loss. Anyone see this before?

 

[KrisReef]

Only suggestion is to clean all the pipes and vents, yes I have seen salt creep ruin the flow in drains, venturi's, etc.

Might be a snail or two crawled in? See that too.

 

[bureau13]

That's all I can think of to do as well. It's been so long since I put this tank together that I don't remember how I did it! A bit terrified of breaking something but I guess if I drain the overflow and some pipes break, I should be able to replace them without anything catastrophic happening. That also indicates how long it's been since this plumbing has seen any sort of cleaning. Maybe it's time!

 

[Tcook]

How long are the strainers on the intakes? I had far fewer issues when I went to the long strainers on my dursos. You can get them, and the complete standpipe if you break it, on Richard Durso’ website. But I agree with Kris that you may have a lot of buildup in the pipes.

 

[bureau13]

I'm pretty sure they are not long like that, but I really do not remember.

 

[Asm481]

You can pull your durso out completely and clean it. You shouldn't have glued it in when you started the tank. Wiggle it back and forth a bit it should pop off. Don't even shut your return off as long as you have room in the sump. That overflow area hold about 3.5 gallons.

 

[bureau13]

I was trying to remember how I mounted it. Hopefully you are right!

 

[bureau13]

Update: Fortunately, the drain pipes were constructed "properly" and I was able to pull them...in this case, they separated right below the T. There is one of those long strainers, and wow, was that encrusted. I think the final nail in the coffin for these things was that globs of bacterial blooms from my carbon dosing (I was wondering where the bacteria was going) was getting trapped since the non-encrusted holes in the strainer were almost non-existent.

I was able to clean everything off pretty well and now things are flowing as they should. Whew!