Angled heads or brushes maybe better.
Less surface sticking friction.
Apart from that.
The bristles could be too strong,or coated.
I would say too many rows,as well.
Less air circulation where needed most...
I dunno,just pondering...
It's sweet though add horsehair,enclose,mini jet in center.
Bee u tee full power squeegee.
Or add jet make housing an whammo filtration line cleaner .