I though I would actually make a post with some advice rather than always asking questions. I just hope it is factually correct.
Since I brought my tub some 5 months ago now, I have been using a very large amount of PH minus and TA plus to balance my tub. On several posts I had read it mentioned that you should never take a reading when the jets are on as this raises the PH. Well this got me thinking, if the air in the jets increases the PH would it save me chemicals if I turned off the air when I am not in the tub. On my tube it is possible to have the pumps ruuning with no air introduced and as the filter cycle runs for 8 hours a day, I though it would be worth a try.
So for the last two weeks I have been turning the air off everytime I leave the tub, so that during the two 4 hour filter cylces I add very little air to the water.
The result is that I have not had to add any PH minus or TA plus for the whole two weeks, whereas I would normally have to add chemicals on a daily basis.
Saves me money and is good for the environment.