All was good until a couple of days ago. Now this...

Our pool water has been very blue and clear. Values all good as well. Nice and stable.

Due to heat and a lot of kids, we lost some water and turned the hose on over night. We put in a tad to much, so husband did a pump to waste to bring the level back down a bit. We noticed the next day that water was a teeny bit cloudy and a very light green. We dumped in some burnout35 (which is what we have been using, and optimizer, again what we have been using). Before we did that we tested our chlorine which 5.0 and CYA between 30-50. PH 7.2
Today it looked a lot better,a light blue but still a teeny bit cloudy and I mean teeny. Still we put in one more bag of burnout at 5 am.

Tonight hubby did a backwash of the sand filter. The color was BROWN, really brown. We ran until clear.

The question is this: When we turned it back to filter, the return shot a few seconds of that same brown water into the pool. The pump/pool is only 4 months old and we have never had this problem.

Thoughts? We were so proud of ourselves for having such beautiful water. I don't need problems right before a big pool party this weekend.

I did a similar thing after backwashing the day before an end of season pool party for my kids soccer team. I guess I should have backwashed a bit longer, as that is the only time it has happened to me. You can try shocking with bleach in case there is organic matter to kill. I would also turn the pump off overnight and see if brown gunk will settle on the bottom of the pool, and if it does, vaccum it directly to waste as they are likely pretty fine particles.

I now only backwash until after events!

After you backwash, you need to put it on rinse for 30 seconds or so to avoid having dirty water reintroduced into the pool.

Thanks! I will do that from now on.

Much appreciated.