stinky ears can be caused from many things. Earmites to infection, bacteria from floppy earred dogs. beagles are floppy earred so likely it is bacterial. check for ear mites first use a q tip and ONLY go just inside the ear canal, earmites on a swab look like coffee grounds. if you have a microscope you can see them well at 500 to 800x. if you have earmite a mitacide is in order. if it is earmites, know they can and do live outside the ear as well, so a good flea bath paying attention to the area around the ears is in order.
to prevent bacterial stuff in down earred dogs i do this.. ...... lay the dog on its side fill the ear canal with strait mineral oil using a needless syringe. hold the dogs ear over the ear canal and massage it gently ( they love it) it will make all sorts of squishy noises, after a few minutes put a paper towel over the canal and turn the dogs head over to allow the oil to spill from the dogs ear onto the paper towel. if you get a lot of junk out do it again. coffee grounds? use a mita cide. bath your dog and know the mineral oil will be around the ears you treated. so soap up accordingly. THE MOST IMPORTANT PART OF A DOWN EARED DOGS BATH IS TO DRY THE EARS USING A LOW HEAT BLOW DRYER blow dry the ears totally. put your fingers around the ear so you can monitor the heat ( i use the low setting) remember you want to make this enjoyable for the dog. when it is humid out i blow dry the ears, when it rains i blow dry the ears no bath just blow dry. If there is excessive hair in the ear canal i pull it with tweezers and my dogs love it and this allows more air flow which with stop stinky ear problems. I am not a vet nor vet tech if you do anything you read online to your dogs check with a professional first. ARE YOUR DOGS EARS REALLY LONG? use a head band a few hours a day ir at night get those ears up and let air into the ear. I hope this helps you it is from my experience with my own dogs
I am not familiar with the ear cleaner that you mentioned above. I tried to look it up on the internet but even on the GoodPet site it doesn't give the ingredients of the product, it simply says that it is "all natural". See how it works. If you are not satisfied with the results, you can always purchase a veterinary ear cleaner from your vet's office like OtiClens or something similar. These types of products are made to dry automatically so that the inside of the ear canal doesn't remain moist. That's the whole trick with cleaning the ears, you want to get the ear canal as dry as possible after the procedure is done, therefore a product that dries on its own is much more helpful than one that does not.
Ghilly