Losing waterfall pressure and not sure why

[texmaster]

Hi Folks,

I'll get the basics out of the way. I have a 2 pump system. One for the bottom drain (no issues) and one for the skimmer (issue) The skimmer pump is a 1/3hp Shinmaywa Norus Series Solids Handling Pump.

Shinmaywa Norus Series Solids Handling Pumps

The ShinMaywa Norus Pumps boast a lightweight design and a corrosion resistant construction, ensuring a long operating life. Norus pumps are fitted with vortex impellers for large solids handling capability.

practicalgardenponds.com

It goes into a Helix Skimmer connected with 1.5 inch pipe that goes around 20 feet into a Helix Bio Mechanical Waterfall Filter and supplemented with an air pump which right now is being replaced. I've noticed a sharp decrease in the waterfall output to the point you can barely see it coming down the rocks but from what I can tell the pump is still pushing out the water (its just a year old) I've drained both the skimmer and the waterfall filter and found mud but thats it. I've tried cleaning out the mud and the air pump is still a week or two away but I was wondering if there are any trouble shooting steps I can take while its down because frankly I'm stumped.

The pond itself is roughly 7x9x3.5 feet

 

[GBBUDD]

More than likely some hair algae, vining plant, or ever some string the wind blew in . Do you have a strainer on the bottom of the pump? Or is there a matala mat inside the skimmer above the pump?

I take it your not loosing water

 

[texmaster]

More than likely some hair algae, vining plant, or ever some string the wind blew in . Do you have a strainer on the bottom of the pump? Or is there a matala mat inside the skimmer above the pump?

I take it your not loosing water

yes strainer and matala mat both. And I'm pretty sure I'm not losing water