Question:
Hello, We have a 22,000 gal gunite pool filtered by an Anthony Apollo Vertical filter(DE). The filter area is 40 (sqft?):here is my dilemma. We shocked, backwashed and cleaned the filter grids today due to heavy rains and significant algae (lots of oak trees overhang the pool). After backwashing there was significant clumps of DE lingering around the outer edges of the grid (near tank walls). Is this possible due to a faulty filtering system that is unable to manage the DE filtering work? Should we use less DE than the recommended 8 pounds for our filter size. How would using only 5 pounds of DE affect the filtering? I guess the real question is how do you know when your filter isn’t working to capacity?
NOTE: I think the worries of algae build up are over “sunny skies ahead hear in Southern New England” finally! Thanks! Lynn
Answer:
Hi Lynn,
Here are some answers to your questions and if you have any others after reading this, please feel free to ask me more question’s below using the comment form on this page.
Your Wrote:
After backwashing there was significant clumps of DE lingering around the outer edges of the grid (near tank walls).
This is actually common and happens to all brands of DE Pool filters and why us pool guys recommend that you open your pool filter at least twice a season and clean it completely out.
After time the spider gasket inside of the multiport valve wears away and then the filter does not back wash as much as it should. Even a new filter system can have clumps of DE inside of it.
Th best way you can take care of the filter is to use the back wash and the “rinse” option more then once every time you back wash meaning, switch it to back wash, then rinse and repeat that process 3 to 4 times and that will help get the inside of the tank even cleaner.
If you filter is a few years old and so is the multiport valve you also could need a new spider gasket.You can usually tell when you have a bad gasket when the pool is running on filter or recirculate and there is water coming out of the back wash line.
You also wrote:
Should we use less DE than the recommended 8 pounds for our filter size. How would using only 5 pounds of DE affect the filtering?
I personally think so and would always recommend using a pound less DE the what was recommended, I always felt that any brand of DE pool filter would run better and I have been working on them for a while now.
Here is a good article I wrote about how to clean DE Filters.
http://wetheadmedia.com/how-to-clean-any-de-pool-filter/
Let me know if you have any more questions and I hope this has helped you.
Joseph
