I use to use one powered by a Mag 5 on my 180 for the longest time.....
Was way too small for my setup at the time but it is a good reactor and it did the best it could
Now use a Mazzei venturi.
Do you know you can run c02 tubing from the vent valve BACK to the pump that runs the reactor so that any c02 gas from the vent will get recirculated?
Tom gave us this idea and it works really well. I did it and it helped a lot.
I gave it MUCH more than 5 BPS for years, it was a steady stream and uncountable.
I think you can raise it SLOWLY (2 BPS is not overkill on a 60) and watch the fish and plants over several days. Remember that the drop checker just helps to know we may be in the ballpark, it is observation and adjustment over time that will tune into your setup. Your final BPS rate my be greater than you think.....
Also as light or plant bio-mass increase, more c02 and other nutrients are needed, so it is not a set and forget thing. C02 can vary over space and time a great deal as Tom is always pointing out and remindng us, so it needs maybe not constant fiddling, but attention just like feeding and filter cleaning, dosing, etc.
I am sorry to hear about your discus........
Hope this helps.