Looking for a good source of pre-maid CDS in USA

I am looking for a good source of pre-maid CDS in USA.

Found a couple on amazon searching for CDS 3000 ppm solution but it is stating that it is for water purification system. Is it safe to buy and to take internally? 

I have never heard of pre made CDS. I don't think there is such a thing. You can buy bottled solutions of sodium chlorite and hydrochloric acid. I believe that is what you are finding on amazon. You still need to mix them to make chlorine dioxide. 

I stand corrected. KVLab sells it. Expensive way to go but.....if that works

No offense to amazon, but they have a lot of counterfiets

Here are some other sources: & some have pre-made CDS
These are sources that others on this site have used:

kvlab.com/

mms-supplement.com/buy-mms

This company ships to both Canada and the US
allonewellnessnow.com/collections/water-purification-drops-wpd-cds
 

You should keep your CDS in a fridge as the gas will evaporate at temps over 50F (11C), according to Kalcker, p.137: "To prevent the rising gas from reaching your nose, it is recommended to drink from a bottle. Drink cold. Below 11°C, the chlorine dioxide does not evaporate into gas."