If you will have access to power, you can also try the 100 watt light bulb in the wet bay. I don't know how the 29.2 grey and black drain lines are routed, but I recently discovered on my 30.1 that about 2 feet of the grey drain line is fully exposed to the outside and not contained in the wet bay. Crawl under the rig and verify that your lines aren't similarly exposed. Otherwise you may be protecting the tanks and having the drain lines freeze up. I don't know how flexible ABS is, but I wouldn't trust it to take a freeze up without cracking.
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