Intex Filter - Sand in Pool

[ScottRDay]

I did a search and found some results, but not my exact situation. We have an 18' x 52" Intex pool with a sand filter. It's been up since early June-ish. We vacuum it regularly and had not had any problems. The other day the pressure gauge indicated we needed to do a backwash and rinse. This was the first time for that. Well, ever since then when the pump runs we get a good amount of sand in the pool. Why did this happen all of a sudden after we did a backwash and rinse for the first time?

And a secondary question is, I saw in some of my search results people mentioning that "laterals" could be damaged. What the holy heck are "laterals"?

 

[Texas Splash]

Laterals are the branches or fingers at the bottom of the filter where water passes through (but not sand) before coming back to the pool. If sand is returning to the pool, and you are sure it's sand, then it's probably because a lateral is either damaged or became separated from its hub connection at the bottom. But try to collect some of that material to ensure it's sand. If it's not gritty and you can't pinch it with your fingers, it may be algae.

 

[ScottRDay]

Thank you for the response. We're pretty positive it's sand, but will test like you suggested. If a lateral is damaged, how do you think that could have happened? Again, we've been running this pool for like two months and vacuuming regularly and this didn't start happening until right after the first time we backwashed and rinsed.

 

[Texas Splash]

how do you think that could have happened?

If a lateral is damaged (cracked), it's really hard to know why. Maybe a manufacturer defect. Laterals can sometimes become separated at the hub connection, but only after inspecting will you be able to know for sure. One other thought ...... even though you didn't have this issue before.... it's important to know you used the correct pool sand (#20 silica pool sand). Avoid the Quikrete brand and any play sand.

Lastly, if it is sand, make sure it's not from a failure to use the RINSE cycle long enough after backwash. Since you noted this only happening after a backwash, it's important to do a very thorough rinse. Once the sight glass is clear, continue on RINSE for a good 20-30 seconds longer to be safe. If that works, then you know it was from not rinsing long enough as opposed to a damaged lateral.