Vacuuming problem...

Our pool is 20years old, we are still using the original pump. It's a cartridge filter, new cartridge installed two weeks ago. It was a disaster when we opened it this year, a lovely shade of hunter green:( Chlorine, chlorine, chlorine, filter all day (turn it off at night usually, maybe that's a mistake?)and clean the cartridge, steadily for ten days. The chlorine level has been 2-3 ppm, ph is 7.5. It is now a cloudy green, but a much lighter shade. Can't see the bottom though. After ten days of chlorine and constant filtering, I added a floculant and let it sit overnight. All the 'gunk' sank to the bottom and I thought 'hallelujah, I can vacuum it up and be done with this'. Nope. The gunk on the bottom is so fine that as soon as I start the pump it swirls up into the pool again, and today it was shooting out the returns as I vacuumed. There is no 'filter to waste' setting on our pump, I guess because it is so old. So every night I let it sit, every morning the water is crystal clear with a 'rug' of green on the bottom. I start up the filter, grab the vacuum (which I have been just leaving in the pool) and try to vacuum again. Everything swirls up and we're back to green again. I can't get the stuff out! I thought that ten days of filtering and chlorine would manage it. What can I do????

This may only answer part of your question, but I don't believe I will be leading you down the wrong path. Has your chlorine been a constant 2-3 ppm? That is low for really shocking your pool. I will let some of the others weigh in here, but I believe I remember reading (and successfully following the directions last year) on the board before all the history was lost, that in order to really kill algae, you might need to be around 20 ppm if you have an outbreak, until you get a handle on it. How warm is your water? Have you isolated it to a filtering issue, or could it be an outbreak that you aren't getting a handle on because your chlorine is too low? Hopefully some others will weigh in, but I think you might be focusing on the filter and it could be a chemical/chlorine issue. Thanks.

Scottturner is right--chlorine of 2-3 isn't going to be enough to kill an algae outbreak, no matter what your CYA level, and may not even be enough to prevent an outbreak if you started with clear water. If you'll please post your current CYA level as well as what type of pool you have, it will help us give you a target chlorine level to kill the algae, which will have to be done before there's any hope of getting it out of the pool. This is going to require raising your chlorine to shock levels, and KEEPING IT RAISED, even if it means testing and adding more chlorine 2-3 times daily. When the algae dies, it will turn grayish, then you can concentrate on getting it out of the pool.

Janet

What Janet said...

And you need to run your pump 24/7. You CAN install a 3-way or 4-way valve between the pump and filter that will allow you to divert water from the pump before it gets to the filter--and that will be the waste line.

If your filter is passing that stuff, then the cartridge is probably seated wrong, or damaged/defective. Cartridges should have no problem filtering that stuff.