Hi My husband says that we have no capability to back wash on this vinyl pool. But I have been scrubbing. Trying to keep the chlorine level up. I only have a five way tester, and I also have strips. I go by the color on the five way. It is really brown. The test strips, the color is on the high side ..I think its over 10 on the strips, 5 on the other. I put in a gal and half a while ago. Swept, ... now later I will go out and maybe add more chlorine, and then sweep. Tonight I will vacuum if its not thundering and lightning. And add another gal and half. Does that sound about right? My pool holds aprox. 4500 gal. Its an intex vinyl.