Let me clarify a few things.

First, there is no limit to flow rate in pipe. The 8 ft/sec is a recommendation.

Second, the head loss in the plumbing is dependent on the flow rate. So on low speed, the head loss is about 1/4 of high speed.

Third, the suction side should have very low head loss since there are three pipes.

I can calculate the approximate head loss in your plumbing but I need a little more information.

What is the approximate length of your suction runs?

For the return to the pool, how many return eyeballs are in the pool and what are their sizes (e.g. 1", 3/4")?

How many 90s do you have in the heat pump install and overall on the pad equipment?

What other fittings do you have on the pad?

With this information, I can determine what the filter pressure should be given your setup and we can see if there might be an issue.