For my tank i've been putting the replacement water in a bucket, putting in the water conditioner (API water conditioner, although i just bought prime cause it was running out), then letting the bucket sit for 48 Hours for the Ph to go down. However by the 2nd day i notice a layer of some sort of Gooey semi-solid substance at the top of the bucket. i remove it with a scooper but a few remains in the bucket. Anybody know what it could be and would it be harmful to my fish? i've done some search and no avail. only possible explanation is i may be using to much water conditioner.