Ice and snow dont want to melt

Try lowering the amount you store to around 2000kg or lower. People have better luck melting it directly out of the storage compactor - it takes up two tiles.

A full compactor is a lot of mass that has to heat up - since the ice all stacks, the temperature gets shared between them. I make my melt boxes out of granite, and only store 10000-2000kg at a time, this melts much faster than waiting 60 cycles for 20,000KG of ice interacting with a relatively small liquid or solids to melt.

 

I put the ice/snow in compactors in my battery room or next to the power generators. This gets a benefit of both keeping the batteries/generators cooled and the water becoming available. I put insulated tiles around the room or I put the batteries in the hydrogen biome to keep enough heat around to melt the ice. It's still pretty slow, but it does work. You can set up a pump with a hydro switch to only drain the water when it would flood the batteries. The hot water from a water purifier will melt it but very very slowly, not really in a useful way. Putting the compactors in that water is more useful for keeping the water (and therefore the surrounding air) cool than it is for melting the ice. If you eventually get a water geyser you can put the compactors in a tank and drain the geyser onto them. Sometimes it won't melt and sometimes it will be hot enough to destroy the compactors, but it doesn't matter because the ice will be there either way.