is any one useing the ultra-low total chlorine test strips from rpc what are pro and con of it?

Not yet, but prefer them over the new strips from Serim. Main problem is even these strips still leave room for error in reading. Do a search on test strips, there's been several threads on this before.
Here's one that may help with the pros & cons:
chlorine monitoring

We are using them. The only issue is ensuring they are verified by the RN quickly as the color tends to change over time. The color doesn't change much, but it does change.

The best thing about the RPC strips is they have more testing points starting at 0.01. The Serim strips only go down to 0.10. This leaves little room for error. We still cannot use the RPC strips with FMC in the units, only the home program.

We use them in our facility. We follow the directions for use from the manufacturer.
Test takes less than one minute.
We have a technician and a RN reading the result at the same time.
All staff tested for color blind.

Guest2 I believe the RPC strips start at 0.10, (someone makes them for RPC)The RPC and Serim strips are the only ones that have 510K clearance from FDA for dialysis (now that Hach strips are not available) Ask the other suppliers for a copy of their FDA clearance.

<Surprised>, The Ultra-Low Total Chlorine Test Strips (#K100-0118)start to measure at 0.01ppm.
We have used them for 7 months now and no problems so far.