25 Meg wall

Hello, We are running a canopy network with three main tower sites, backhauled back our servers with a 40 meg fiber connection thru a mikrotik router. I have tried accessing the internet thru each tower site, and when our network traffic approaches 25 megs we start having issues with everything slowing down.
We have ctm-1m,netgear and d-link smart switches connecting everything, and cant find any reason why we should be having slowdown issues like this.
Has anyone ran into a problem like this? Hope thats enough initial info!

How are the towers fed? Have you troubleshot the Mikrotik?

two towers are fed with canopy 20 meg 5.7 backhauls, 100% up and downlink, and the third is fed with a 45 meg trango, 0% error rate.
When testing, i can move my test gear around so i am going thru the different sites, which leads me to believe a problem with the switch or the mikrotik, however, when plugged in to the switch right in front of the mikrotik i seem to have no issues pulling down all of our bandwidth.
How would you test that mikrotik?

How are the backhauls connected to your Microtik? Can’t you just plug in beside them?

What is the actual throughput, not link efficiency, on the Canopy BHs? Max aggregate on them is about 14.5mbps, we usually run them at 90% downlink for 13 down 1.2 up. What’s the up/down throughput on the Trango?