Pool fill of water

Fill it from your tap it will be much cheaper 

Hello. You can use Galasa BUT send them an email of roughly the date you intend to refill. That way you will not receive a warning letter that you must have a leak.  Email - sat1@galasa.es   you should receive a reply just saying gracias or ok. 
There may be other responses that you should not use Galasa especially from those operators who supply “tankers of” water refills.  From memory was €160 for an 8 x 4 pool which was really cheap!!