Pool guy says I need to add sand to my filter because the sand dissolves over time. Is this true?


In The Industry
May 24, 2016
A serious company built the pool and installed the machinery. Also, I haven't had any problems for the last 12 years so probably the amount of sand was ok. This guy just stuck his hand in and said it was low. I estimate it was a little over half full. He then went on to tell me that the sand dissolves with time, which it seems is untrue.
Never heard that one before. I didn't know all these years I could have been topping off the sand filters instead of changing the sand out. Don't let him add more sand unless you have him change the old sand out first. Mixing a few bags of new sand with the old sand isn't going to improve anything.
Also the sand will feel loose and free in the middle. Down along the inside walls all the way to the bottom is where the real gunk collects.

Those Tr 100 sand filters are 600lbs. 600lbs of sand takes you to the top line just at the diffuser pipe. Thats where everyone I know fill them to. Thanks for posting those charts.
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Aug 27, 2021
The filter is 30" in diameter, which is 4.9 square feet.

So, the backwash flow rate should be about 73.5 gpm.

I think that you might have a SW5P6RG1, which is rated at 27 cubic meters per hour (119 gpm).

So, the pump is oversized for the filter and you could be losing sand during backwash.

View attachment 367875
Is there a way for me to check this? I may be losing sand but I may not, how do I test?
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