Previously with the APS 2000L/H I tried extending the spraybar , it comes about third lengh of tank, but at the end it comes out with a lot less pressure Think in these situations two filters spraybars meeting in the middle may be the answer.
Zozo Have you got a sketch or photo?
IMHO Connecting one spraybars at both ends won't perform significantly differently to two spraybars placed end to end. (The same configuration, but cut in half and then plugged.)View attachment 164331
I mean this, spray bar connected to both sides, to one T or Y connector. That's the loop and water will come from both sides meeting up in the centre... Then the pressure is equalized over each hole in the bar.