We have been having many problems with our DE swimming pool filter. Our landlord does the winterizing and we question if he does it properly.
We have used 36 pounds of pool chlorine, 2 lbs of anti-algae, 2 pounds of phos clear, and almost 65 pounds of DE all in one week to clear up our pool. The chemicals were given when we brought various samples (5 times) to the local pool store. It has been 8 days and $350 and we still have a mess of a pool.
It is an ground 25,000 gallon and uses a DE swimming pool filter EC75. There is DE in the bottom of the pool. We cannot vaccuum as there is not enough suction. We have been bumping constantly.
We just took apart the filter and two of the tentacles are ripped, with fabric hanging off.
Thanks for your questions Matthew
When you say, "It has been 8 days and $350 and we still have a mess of a pool," I will assume you probably have a pool algae issue. To shock a 25,000 gallon pool you would need 6.5lbs. of granule pool chlorine (Calcium Hypochlorite) or 4 gallons of liquid chlorine (Sodium Hypochlorite).
With 36 lbs. of chlorine your readings would be off the chart. When I shock the YMCA pool I use 35 lbs., and that's for an 80,000 gallon pool. I think you might be getting the wrong information. First, get a Taylor Reagent FAS-DPD K-2005 or 2006 pool water test kit. This is the most accurate.
Next is to check your DE pool filter. My experience has been if less than 50% of the grids are torn or ripped you can try to repair them. If you're unable to to sew them back on you can get a local pool tech to come out and do the repair. If more than 50% are ripped you might think about getting new grids.
Your filtration system might be clogged with DE. Take it apart, clean it if necessary, and add fresh DE. Follow the directions for adding DE to the letter. More is not better. DE in the bottom of the pool would indicate ripped or torn grids/tentacles and also a clogged system would lose suction.
Be sure the skimmers, pump basket, and bottom drain are free from debris. Have your water level 1/3 - 1/2 up from the bottom of the skimmer. Be sure any plugs from the pool winterization are removed. Check the skimmers and returns.
Allow your filtration system to run for an hour or so to ensure no DE is coming back into the pool and everything is circulating and running properly. Scoop any debris from the pool with a leaf rake, not a blue skimmer.
Once you've done the above and everything is cleaned out and circulating, it will be time to shock the pool. Go here to see exactly what you need and how to do it.
Chemicals that reduce the amount of phosphates in the pool should only be used in extreme conditions. Algae needs phosphates to grow, but when the pool chlorine level is kept between 1.5ppm - 3.5ppm there's no swimming pool algae. If there's no algae, then does it matter what the phosphate level is? Once you get the circulation up and running you'll be able to vacuum.