Regarding your question, I did not use any external render farms except for my two computers (2 GPUs) here in the office, which took approximately 1 week to complete.
another very beautiful work of yours … I have a question too, I was checking the material node and realised that you use very simple nodes for the glass and water object in the scene, is there any particular reason behind it ? plus what does the light path node is doing for the water?
thanks
I always make it a point to make my setups as simple as possible–for ease of use/modification, faster render times, lighter file size, etc.
Regarding the light path node, what it does is it tells Cycles to render the glass transparent when shadows hit it–to save time and to make the rendering faster.