When do you replace/add Sand to a Sand Filter?

[UnderWaterVanya]

I am the newly appointed pool boy for my father-in-law's new (old but new to him) pool. The pool was not maintained but was covered for a couple of years. I'm not sure but I think the filter was in operation at this time. The water was pretty good when the cover was removed. In any case, I know little about sand filters other than the very basics. I have a neighbor with an AG and he has taught me a few things but does't use BBB. He used playsand when he replaced his filter - which I think I read was a no-no. I would like more info on what the process is to determine when you need to add or change the sand.

 

[linen]

For replacement, in most cases, never...the prevailing opinion on here (mine as well) is it doesn't "wear out". Two exceptions I can think of. One, if you do not know you have the correct sand volume, then removing and replacing with a known amount might make sense. Secondly, if you sand has become heavily calcified, so that it has a propensity to channel and reduce filter efficiency.

As for adding sand, some filter instructions show where the level should be, but most don't, so as mentioned above, the easiest way to know is to refill with new sand of a known weight. If the filter is working properly, you should never loose enough sand to need replacement.

Are you having problems filtering?

 

[JasonLion]

The sand should be fine. The only thing that forces you to replace the sand is heavy scaling, and that is fairly rare. If you want, you can open up the filter and check on the sand and see if it has gotten clumped up or anything like that, see this post for details.

 

[UnderWaterVanya]

As far as I know I am not having filtering problems. I'm new to this stuff so I'm not sure how to tell. Water is clear but something may still be alive in it since I have not quite passed the OCLT. (19.5ppm dropped to 18ppm from 1am to 9am no sun on pool). I see some very fine floating dots in the pool light at night my wife says they are bubbles but I don't think they are. They look white in the light and they are tiny. Also I have increased from 14 hr / day pumping to 20 hr / day during my initial clearing of an algae bloom. Filter has been on the 20+ schedule for days w/o much pressure rise. But the water is clear. Previously I did see a rise in pressure when the water was cloudy. I backwashed, since then slightly up from 10 psi to maybe 10.5-11.

Thanks for the advice and Clarification.

 

[Isaac-1]

It may take a sand filter several days after everything is dead and you pass the OCLT to filter all the particles out of the water.

 

[Qwaxalot]

While the sand may be fine, it's not that big of a deal to replace it. However play sand is NOT OK.

Filter sand does deteriorate. It gets calcified and rounded off. Hence manufacturers recommend replacing sand every 5 years. Clumping and calcification are different issues, more related to water chemistry.

 

[Bama Rambler]

Qwaxalot, you apparently haven't seen the microscopic images of the brand new sand and the sand out of a filter used many years. You can't tell the difference. If water running over it wore it out there'd be nothing but dust or little round balls of sand on the beaches.

Granted, calcification can ruin sand but even that's a rare occurrence.

Do a little research here before spouting the industry line.

 

[applgrl]

Bama, I'd love to see the pix of before & after sand. We've only replaced our sand once in 40 some odd years, and only because we re-plumbed the pool and thought, well.....maybe we should. No visual difference, no dif in performance after changing the sand either. One reason manufacturers might want you to replace it every five years is that you will wear out the bolts & gaskets more quickly and have to get a new filter. We were very worried our old, old Jacuzzi wouldn't go back together in one piece. But it did....whew.

 

[linen]

http://www.troublefreepool.com/sand-filter-expert-help-t30049.html#p247326