After I dosed CP to my DT, I was worried that the CP would last forever. Fortunately it didn't. Here is a recap below for anyone that might do as I did and medicate a fish only tank with CP. I'm no expert, just a hobbyist, so take my experience for what that's worth.
I initially dosed CP at the recommended level of 40mg/gallon into my DT. I didn't experience any ammonia issues and the biological filtration seemed to continue working as far as the skimmer goes. All algae died off the rocks. The fish were fine but all inverts died. Most of the copepods also died. The glass on the DT stayed very clean during treatment.
I did two 20% water changes after the first month and another 20% water change just recently. I skimmed very wet after I got to the 1 month mark. I also ran carbon after the first month was over and some more recently.
After the second month I added a bottle of copepods. I didn't see much pod activity at first but more recently the copepods multiplied and returned to excessively healthy levels as you see in the video. New inverts and snails are all doing fine now.
In all, the tank is back to normal and there are no parasite issues to worry about. It was close to 90 days from day 1 of CP treatment to get my DT back to normal, which was longer than I expected. At least it got back to normal.
The dosage instructions followed:
Typical dosage for quarantine is 40mg/Gallon (app. 1/8th tsp./10gallon) for ten days. This is a one dose treatment.
If water changes need to be performed to reduce ammonia, then chloroquine phosphate needs to be redosed for amount of water changed.
10g treats 250 gallons...25g treats 625 gallons...50g treats 1250 gallons....100g treats 2500 gallons.
For treatment of existing*Cryptocaryon irritans(ich), Amyloodinium ocellatum (marine velvet) and brooklynella (brook) up to 80mg/gallon (app.1/4th tsp./10gal) can be used.