It works

No leaks in the reactor, that is amazing All four on my tanks had a slight leak somewhere. I had to tighten one of the connections up initially on each one (mostly the CO2 nipple) but no leaks after that. I think that is the first one that hasn't leaked. I don't think Jack has his hooked up yet to give any input.

You shouldn't have any dead fish with the controller as long as the KH stays steady. The KH shouldn't change except maybe after a water change. I ALWAYS test my KH an hour or two after the water change to make sure it stays the same.

I don't think it will be long before you start having extra plants to bring along or give away. I'll bet the tank is pearling when you get home tonight!

I think Jack is worried about my DIY reactor leaking

I still think a reactor is the best way to get CO2 into the tank especially larger ones, say over 30g or so. Whether you use an external or internal one is personal preference. I don't like the extra equipment in the tank but that is my opinion. Takes away from the amount of plants I can keep in the space.

All I can say is pick one and get er done! You can always hook up the DIY one I gave you until you figure out something else or get another one built. Assuming you have a canister filter that is.