i need help with my durso standpipe

[John 3:16]

hey, i built a durso standpipe about a month ago and it was working very good. Yesterday, i notice that it is draining to fast causing a sucking noise and the water level in the overflow is at the bottom of the drain hole. This morning, the overflow would drain untill it started making the sucking noise and then in would completly fill the overflow submerging the standpipe. i haven't done anything different i that i know of and it worked great for a month .
Anybody know whats up with it

 

[John 3:16]

oops sorry i did it twice

 

[kaotica]

could it be due to water evaporation? top it off and see if it still does it

 

[Big R]

Clean your hole out. I mean the one on top of the standpipe.

R

 

[John 3:16]

i did both of the above suggestions
any more help

 

[John 3:16]

i did both of the above suggestions
any more help

 

[John 3:16]

man this thing keeps posting twice sorry

 

[bezzer]

John 3:16

Take a look at the other post you have going about this same issue. I have suggested other steps you might consider.

Brian