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gallathan · 16th August 2007, 13:31

just thinking about blending heliar diluents vs blending trimix. Think blending trimix in dil cylinders at home may be error prone, so tempted to think about heliair, but have a dilema.

Seems you can go 2 routes, 1) Keep the PO2 of the heliair the same as my trimix dils i.e. 1.0. As heliair has a fixed N2 to O2 ratio (79.1:20.9) that results in high END's ~ 37/38M. I know the oxygen added by Rebreather to go from PO2 1.0 to PO2 1.3 will dilute the diluent a little, thus reducing the END, but not a lot.

2) Go with a dil with a PO2 of 0.836 instead of the 1.0 I normally use for Tx diluents. This is perhaps not the most optimal diluent for loop flushing, BUT does result in an end of 30M, like my timix bailouts, but concerned this will result in Rebreather having to add more O2 to the loop - reducing O2 duration and/or leading to more buoyancy issues.
Whats the normal practice for choosing a helair diluent, how do these factors get balanced?

16th August 2007, 13:31	#1 (permalink)
gallathan New Member Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Mar 2006 Location: Laleham, Middlesex, England, UK Posts: 52	heliair vs trimix just thinking about blending heliar diluents vs blending trimix. Think blending trimix in dil cylinders at home may be error prone, so tempted to think about heliair, but have a dilema. Seems you can go 2 routes, 1) Keep the PO2 of the heliair the same as my trimix dils i.e. 1.0. As heliair has a fixed N2 to O2 ratio (79.1:20.9) that results in high END's ~ 37/38M. I know the oxygen added by Rebreather to go from PO2 1.0 to PO2 1.3 will dilute the diluent a little, thus reducing the END, but not a lot. 2) Go with a dil with a PO2 of 0.836 instead of the 1.0 I normally use for Tx diluents. This is perhaps not the most optimal diluent for loop flushing, BUT does result in an end of 30M, like my timix bailouts, but concerned this will result in Rebreather having to add more O2 to the loop - reducing O2 duration and/or leading to more buoyancy issues. Whats the normal practice for choosing a helair diluent, how do these factors get balanced?
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