I bought a new tub which is a Hydropool Serenity 5000 and when cleaning the filter it says in the manual to put the tub in hold standby mode to stop filtration when cleaning the filter. The book says to press the down temp button and repeatedly press the light button to get the hold standby function to work. I tried this as well as holding down each temp button and the up temp button by itself but it will not work. I am sure I got it to work once before but now its not working. I called my dealer and they told me I can remove and clean the filter without it being on hold. Will this damage anything if the tub has no filter in it and it tries to filter? Even if I do not need the hold function it still should work otherwise something is defective.