Question: Which chiller to purchase?

I am looking for advice on an aquarium chiller for my 20 gallon tank with one axolotl. I use a Marina Slim filter (S20) and a sponge that works to dissipate the water flow.

I am willing to spend money on something that works - I am not looking to have a fan set up or use frozen water bottles since I will be out of town for a month this summer and need an easy set up for our house sitter and I want a stable environment for him.

I've looked at the AquaEuro USA Max-Chill Titanium Aquarium Chillers 1/13 HP, but I have no idea how to set it up and what kind of extra tubes and pumps I would need.

If I purchased something like this, do I have change my filter set up? I'm not sure where to begin. Thanks for any advice you can give!

Those are good chillers. I have 3 tanks and 3 of these chillers - they work really well. There are two ways to setup. With a pump or with a canister filter. My tanks all have canister filters, so the setup is inflow tube to canister filter, outflow from canister to chiller and another outflow from canister to spraybar. This setup is good as it sends filtered water through the chiller which I think will help prevent gunk up of the machine. In fact the chiller instructions mention that the water needs to be filtered.

The setup is similar with a pump. The pump goes in the tank with a tube to the chiller and then another tube from the chiller back to the tank.

Note, these chillers do not come with tubing or the pump so you will have to purchase those separately. And if you go this route you may want to find a spraybar as well to hook the outflow tube so the return chilled water is dispersed. Axie's don't like a lot of water movement. There is a you tube video on setup of one of these; just google AquaEuro chiller setup. I did purchase a pump, but never used it - PM me if you'd like to buy it.