First, you need to decide what kind of temp measuring device you want with what functions.
The type @Nedman suggested provides temp readings for two probes in one unit but it does not prevent an over-temp. i.e. you have to keep an eye on it.
Its wiring is simple, you have to provide power to it. If you have nothing else connected to your LPS 24VDC you could connect it to the 24V on that stock supply. I am assuming that this meter draws a small amount of current. That said I would add a 12V supply as it can be used for other stuff including a cabinet light. I do not like loading the stock supply as it is already marginal @1amp.
The type I suggested does provide over-temp protection but you will need two meters of this type if you want to measure the bucket temp as well. In this setup, the relay in the meter is added in serial with the water protect circuit which will shut down the laser in the event the water gets over a setpoint you load into the meter.
In my garage setup, I added an aquarium heater which has an integrated temp probe and meter to keep my water from freezing when not in use in the winter. In this way, I have a meter and to-cold temp control in the bucket.
In this setup, I get measurement, tube protection and water heating with two meters. This set up is obviously more expensive and complex to wire and set up. That said since you should already have interlocks wired into the laser power circuit you can just add this meter as well.
This is not intended to suggest one way is better than the other just different costs and functionality. As always upgrades are full of cost/function tradeoffs.
@Nedman jump in if you have different advice!