I develop FP4+ in Rodinal 1+50 and face similar problems - i.e. tap water and ambient temp too high in summer and too low in winter for my preferred 20 degree C dev times. I am in Sydney, Oz where in summer tap water temp can be 25+ degrees and ambient in the high 30s... In these circumstances a water bath is the way to go.
The trick is to use a sufficient quantity of water in the bath, and a non-heat conducting container to ensure the water is impacted by ambient temp as little as possible. My water bath is simply a plastic tub that sits on my bench. It takes about 10-15 litres of water. Once the water in the bath is at 20 degrees C, it holds that temp +/- about half a degree for my average 7-10min dev times. (I use a Jobo 2551 tank sitting on a roller base in a water bath).
Hope this helps
Carey Bird
http://members.iinet.net.au/~cbird/index.html
The trick is to use a sufficient quantity of water in the bath, and a non-heat conducting container to ensure the water is impacted by ambient temp as little as possible. My water bath is simply a plastic tub that sits on my bench. It takes about 10-15 litres of water. Once the water in the bath is at 20 degrees C, it holds that temp +/- about half a degree for my average 7-10min dev times. (I use a Jobo 2551 tank sitting on a roller base in a water bath).
Hope this helps
Carey Bird
http://members.iinet.net.au/~cbird/index.html

