Kathy,

Don't throw the bag in just yet. Water should not wear out in 3 years.

So, by your response you have been vacuuming into the sand filter I assume.

To backwash you need a backwash hose that should be attached to the filter. It is rolled up and usually blue in color. If you don't have one, get one from your pool store. You will need a clamp too to hold it in place. Roll out the hose so it can discharge. Turn your filter off. Move handle clockwise to backwash. Turn filter back on. Water should flow through the blue hose. Check the little plastic bubble near the top of the filter housing on the side. It will look sandy in color. When it appears clear, stop filter. Move hand to rinse. Run on rinse for about 15 to 30 seconds. Stop filter again. Turn handle to filter. Start your filter again.

To vacuum to waste, roll out the blue hose. Remove all air from the vacuum hose by placing hose in front of the return. The place vacuum hose into skimmer throat (remove basket first). Turn filter off. Move handle to waste. Turn filter back on and water should come out the blue hose like backwashing (except at a slower rate). Vacuum bottom. Then follow procedures by turn filter off, removing hose, replacing basket, move handle to filter and turn on. No need to backwash yet.

Keep chlorine up. You do need to know how much CYA you have in the pool so you can know how much chlorine we need to get it at to kill all the things that are consuming your chlorine.

Make sure you try to keep PH around 7.5 Deal with the TA later. Even a PH as high as 7.8 doesn't inhibit the effectiveness of chlorine that much. Constantly aerating will cause the PH to rise.

The key is to do one thing at a time.

Hope this helps.

Harry