From what I read and saw here in the forum. The cleaning solution only cleans the mop heads. I also read that you can add a little to the tank but I didn't read that off the official Dreame site. Some people said the had put a cleaning solution on the mop pads themselves. It was a Dreame support person that answered in this forum that the cleaning solution is only used to clean pads and not the floor.
I didn't know that until I had been using it for a week. My floors are immaculate! I would think even though it only washes the pads with the solution some must stay in the mop heads material and when they get wet again there is some cleaning solution on them. I had my family and myself walk around with new white socks rubbing their feet into the floors and no dirt! I am really shocked at how well these machines work

When I ran out of the solution that came with it, I refilled with Shark solution in the little black water tank. But I also add the same Shark solution to the clean water tank. Floor stays clean with just subtle hint of the fragrance.

Hi,

For models that support automatic detergent dispensing, you can pour the cleaning solution into the detergent box—the device will add it automatically.

For those that do not support automatic addition of cleaning solution, you can manually add cleaning solution to the clean water tank.
The cleaning solution ratio for Robot Vacuum is 1:200 in milliliters (ml). This means you need to mix 1 ml of cleaning solution with 200 ml of water.

For devices (those below the X50 model), the cleaning solution is only drawn to clean the mopping pads when the pads are being washed at the base station; no cleaning solution is dispensed during the mopping process. While the solution is not directly used for mopping, it will ultimately still provide some floor-cleaning effect.

If you wish to add the cleaning solution to the clean water tank, it is recommended to use only a small amount. Adding too much will generate excessive foam, which will cause pipe blockages.

Additionally, it is not advisable to use cleaning solutions from other brands, as this could damage the device's pipes or water tank, or lead to other issues.

Can i use any cleaning solution or does it have to be the specific brand?

Dreame recommends their brand as the rep just stated in last sentence. I only use their brand as I don't want to clog up anything and it is low sudsing which it has to be.

I just unboxed the L40 Ultra gen 2 and I don’t see any solution. Is the cleaning solution part of item?

Ditto l 40 ultra gen 2

It is supposed to come with a small bottle of the cleaning solution, it’s supposed to be in the supplies box that comes with the machine.

I also did not receive a cleaning solution bottle to add to my clean water tank… I just got the L40 ultra gen 2…