The intent of Isolation Tank Gnosis is to reduce the impact of sound, gravity, skin temperature and light on the recluse.
With that in mind, let’s approach the factors we aim to reduce systematically, starting with sound. This factor requires the most attention from you as an Abba. The tank itself will deal with the other factors just fine. But the need to supply air to the tank implies that sound can travel to the tank as well. So keeping 8 weeks of quiet for the Recluse is the responsibility of the Adytum, Abba, and Temple. Perhaps the Recluse likes earplugs, so have some on hand. But all in all make sure that the Adytum, Abba and Temple are reasonably silent for the Recluse. Granted, the Quiet Center is ever-present, even in a hurricane. But the first steps towards the Voice of the Silence are best taken in seclusion.
Regarding gravity, the tank will handle this just fine as long as the salt and water levels adhere to the measurements laid out in chapter 10 of the “The Deep Self” by John Lilly – “Standards for Isolation Tank Manufacture and Reuse”. Salt levels can be maintained easily if you fill a small container with epsom salt. The container should let water in but prevent undissolved salt from exiting. A burlap sack makes a good choice. As the water dissolves the salt and the concentration demands more salt, the salt will make its way into the tank. As far as water, you might take a few teaspoons of water with you each time you exit the tank. So putting a cup or so back in per week should keep things at the suggested height of 10 inches. With all this being said, experience has shown that 8 weeks of floating do not significantly deplete either water or salt.
Regarding temperature, the tank will keep the water and skin temperature of 93.5. The adytum should be temperature-controlled. I maintain the room at 82 degrees fahrenheit. Having the adytum a bit on the cold side allows the body to radiate heat, which it does for the first hour of a float anyway. After an hour a person’s mind has dropped most of its clinging for preferences and the actual need for a precise temperature will attenuate. I once designed a tank that did not use heaters while the tank was in operation. I floated for 8 hours on my birthday with no sense of discomfort. The water had dropped quite a bit in temperature (I can’t recall the exact reading. I think it was around 82 degrees).
As far as light, I find that most tanks do a good job of attenuating light. A related issue is how to provide lighting as the Recluse temporarily departs the tank for food or the bathroom. I like motion sensitive lights for this purpose.