backwash water goes into pool

[Furbabyvet]

I have a sand filter and noticed that after every time we backwash, the pool looks a lot worse. I've actually watched brownish water flowing INTO the pool while it is being backwashed. This is more than just a little sand, I mean the whole pool is cloudy after we do it. I don't see how this can be right, but in my ignorance, I've never done anything about it yet. Just try not to backwash very often.

I'm currently fighting and winning the battle against what I believe to be some serious mustard/brown dust algae, thanks to the help I've gotten here. I'm dreading backwashing the filter, which needs it soon, because the pool will be brown again for a day or two! We have followed the procedure in the manual EXCEPT opening the air release valve at the beginning of the backwash procedure. Would that cause the problem or do we have a plumbing error?

Bless The Pool Forum. I feel I finally have a grasp on all of this!

[CarlD]

Ouch! Something is plumbed wrong or assembled wrong!

What brand and model of pump, filter and multivalve do you have, and what kind and size pool?

Your multivalve should have 3 openings large openings: From the pump, to the pool, and backwash waste. They should be marked on the valve. If they are correct it's possible the multivalve is assembled wrong, such as with the spider gasket incorrectly placed, or the wall between two chambers in the valve broken. Unless there's something esoteric going on, that's your most likely culprit. I'll let the folks who are more expert on multivalves give a better explanation

[Furbabyvet]

Stats on our situation:
11,940 gal. Pebble Tech pool. New 1 hp Sta-Rite Dyna-Pro pump (we had this problem before the new pump was installed). The filter is a Sta-Rite high rate sand filter model hpb24, 3.1 sq. ft.. We had the sand changed out a couple years ago. We have a Hayward Pool Vac Ultra in the pool, too.

Next week, we have a service coming to change the way the filter discharges backwash water. The former home owner had it plumbed to drain into the common area of our subdivision which is a big no-no. They are going to put a regular hose in (I guess) so we can be legal and drain on our own property. I was hoping to figure out this plumbing thing before they come next week.

Thanks a lot!

[BigTallGuy]

In an effort to answer your question, how much water is going back into the pool when you backwash? Does it gush, or is it a trickle?

I had a similar issue on a different brand name sand filter. When I ran the filter in the normal filter mode, a trickle of water would discharge from the backwash hose. My problem was the spider gasket inside the valve. Once I replaced it, all was good.

[waste]

Unless a huge error was made, as Carl suggested - I think BTDG has hit the nail on the head. Open upi the top of the multi and see how the gasket (spider gasket or wagon wheel) looks and d the channels it sits in.

If you need help figuring out what you find inside the multi, you can search some of the old threads or just ask us.

Welcome to the forum!

[Furbabyvet]

OK, let me clarify and amend my question. We just backwashed and I watched what happened. No water went into the pool during backwashing, but when we turned it back to regular filter mode, lots of cloudy water went into the pool. We don't have a "rinse" option. Do we just need to let it backwash longer? Doesn't seem like cloudy water should go back into the pool as badly as it is. Our entire pool now looks milky and it was clear before .