Aqua running energy expenditure

I have an ankle injury (physio suggested a repetitive strain injury) so have been advised to not run for two weeks but with a half in mid September I want to keep my fitness up. I have been cross training (swimming, rowing etc) and have now started aqua running; I did 75 mins session yesterday (5 min warm up, 3 sets of 8x1:30, then 20 mins cool down) and a 45 mins session today (5 mins warm up, pyramid intervals from 1 mins up to 5 mins and back with 1 min recovery between each, 5 mins cool down). I felt I was working hard but not sure how the energy expenditure compares with land running and I want to make sure I don't lose weight; during previous injuries I have found that cross training does not make me as hungry as running so have dropped weight and I think this has hindered my recovery. Although not as underweight as I was my BMI is still less than 17.5 so need to be careful. I have searched online for calories expenditure from aqua running but it seems very variable! Any advice would be appreciated 

Sounds like you should get yourself weighed weekly to make sure your weight is staying level anyway, if you've had difficulty keeping it on before.

Off the top of my head (having done a bit of aqua jogging) I would think it's about halfway between cycling and running. You could try that to start with and then throw in a bit more grub if you still lose weight after a week or 2.