Backwash runs clear...green pool.

[Jktbnelson]

Hello,
I have a [FONT=&quot]23" CaliMar® Sand Filter System with 1-1/2 HP Pump on a 27' round AG that I put up 7 days ago. I did the initial 'backwash to clean the new sand' as directed and didn't notice any color change in the bubble. I backwashed today (1 week later) and again the water was crystal clear in the bubble window and now my pool is green. My question is: with the pump and sand being so new and the water, up until yesterday was pretty clear, would I expect to see dirty water? The pressure reading has been steady and the return is strong. I did add a metal out liquid 3 days ago and shocked yesterday. Does the metal out sometimes appear as a green color? I know we have iron in our water and usually presents as a brown color. I will test tonight and see if my chlorine gets eaten up by tomorrow morning to confirm algae, but I was just wondering if my pump was cleaning like it should be?
My readings today with green color:
FC: 3
pH: 7.5
TA: 120
CYA 30-50
Thank you,
Kari

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[DaneCE]

After only 7 days you shouldn't see much dirt moving through the glass unless you recently had a storm that brought in a lot of dirt. You need to stay on top of your free chlorine levels!

 

[Richard320]

If you wait to backwash until the filter needs backwashing, you'll see plenty of color in the waste water.

Look at the pressure gauge on the filter now. That's your clean pressure. When it rises 25%, then you backwash. One week in after a fresh fill, I'd be astonished if there was enough filtered debris to see.

You'll be fighting a constant battle with metals. The sequestrant binds to the metals and the water clears. But then it breaks down over time, and chlorine also degrades it, so you have to keep adding sequestrant periodically. Odds are, when you "shocked" the pool, you accelerated the breakdown, so some color reappeared.