I let my ph go low, now I have trouble

[JimTMich]

I let my pH slide low this year down to 6.8. It's been slowly sliding since I opened 2 months ago. I finally brought the ph back up to 7.2+ and the liner got brown stained, the water got a little cloudy and has a green tint.
Fc 8
Cya 100
Ta 100
Ca 140
Ph 7.2+

Ascorbic acid test takes the stain out.
I added some good metal out and some iron precipitated out on the bottom of the pool.
It's been 24 hours. Water still looks green and slightly cloudy. Stains are lightening a little.

What's my next move?
I could drop the ph and get the copper and iron back into the water then do some water changing.....

 

[cowboycasey]

I wish I knew more about metals in water, but I do not. From you numbers the CYA sticks out to me, do you know for sure your CYA is 100, that is the highest a CYA test will go. also with a FC of 8 your barely above minimum of 7 for your CYA level, are you taking the FC above or to 12 every day?

 

[JimTMich]

Cya is probably a little higher. I should try diluting and run the test again. Chlorine seems to be holding. I haven't been shocking daily. I should probably break out the big kit and make sure. I do have non copper algecide 60 in the pool.

 

[morzh]

With CYA this high no wonder chlorine is holding.

 

[JimTMich]

Cya 160
Fc 6.5

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So do I slam first or dilute first?

 

[cowboycasey]

so, poolmath says to go from a CYA of 160 down to 50 you need to replace 70% of you water...

If you empty 50%, that would take you down to 80 CYA but your SLAM level would still need to be above 31 FC and that is a lot of bleach, you really need your CYA between 30 and 50 to do the SLAM...

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you need to know your water table level before you empty more than 40% of your pool water, you do not want your pool to pop/float out of the ground..

 

[JimTMich]

No. I've lowered to 12" in shallow end successfully several times. That will get about 40% of the water by my math. So will have to do that twice to make some headway.

 

[pooldv]

I don't know much about metals either, here is an article from pool school, Pool School - Metals in the Water and Metal Stains.

You should dilute CYA before SLAMing. With CYA of 160 the shock level for your SLAM will be 62 ppm. Chlorine CYA Chart

 

[JimTMich]

Thanks all for helping me see the alge problem! Pumping the pool down now. I need to ban trichlor from my pool! Swg or liquid is in my future.

 

[pooldv]

Good plan!

While you wait for your pool to drain how about adding your pool info to your signature as shown here, Pool School - Getting Started

 

[JimTMich]

Good plan!

While you wait for your pool to drain how about adding your pool info to your signature as shown here, Pool School - Getting Started

For some reason my signature only shows in the first post. I'll look for a setting.

 

[JimTMich]

Drained and replaced water with city water. About 4,000 by adding water in the deep end while pumping out of the shallow end followed by 10,000 refill. (total volume of pool is estimated at 20,000) water added as measured by the city water meter.
Shot home at lunch to turn the water off.
TA 120
pH 7.2
CYA 80

So I added 68% cal hyp to get to slam level of 31. Confirmed.

Just then the reinforcements arrived with 20 gal of 12.5%.

So I added liquid to get to 44 to hold it over till after work.

 

[cowboycasey]

perfect, your CYA will continue to go down when you backwash, you can make it with a CYA of 80, you already know where you have to be at to SLAM.. If you need anything ask away and we will try to help

Try to keep your FC above SLAM level, so for CYA of 80 you want it above 31, so shoot for 35/36 and let it fall to 31 and do again.. Your SLAM will go much faster

 

[JimTMich]

6 hours later:
FC 44......

So in 6 hours the FC hasn't moved from the initial slam. Water looks the same......

Doesn't seem like it should have held at the calculated first dose if there was an algae problem.

pool is still light green and lightly cloudy.

The good news is that the CYA is in a much better spot and I'm motivated to kick the Tri-chlor habit.

Any thoughts on what is going on and what I should try next?

 

[zea3]

You did say you had iron in the pool? Did a test confirm this? Is the water clear green or cloudy? Is your liner blue?

 

[JimTMich]

You did say you had iron in the pool? Did a test confirm this? Is the water clear green or cloudy? Is your liner blue?

I have a stain on the liner that comes off super easy when touched with vitamin c. Added metal out and a bunch of rust fell out of the water and landed on the bottom.
Water is slightly cloudy green. Cannot see the bottom of the deep end.

This all started with 2 months of 6.8 ph. When I corrected the ph, the green and brown stain appeared within 24 hours. Crystal clear before that.

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Liner is light blue

 

[JimTMich]

We had a big rain storm last night.

FC 34 this morning.

 

[JimTMich]

The light of day reveals that the alge is dying! Starting to flip to the white cloudy blue!