Bromine Chemistry Question

[FormerBromineUser]

Thanks! I bought 4 quarts of polyquat on Amazon. I hope the link you gave me went through the forum!
I vacuumed the pool to get rid of the auto-cover installation crud and backwashed before putting in DE. The backwash water was dark burnt-orange. Yuck.
Should I add more DE tomorrow night? How do I know when to stop adding it daily?
I will report chlorine results Friday morning.
BTW, thanks for cleaning up my signature. Much better!

[PoolDoc]

Orange backwash = iron in the water

Wonder how that got there? Am I forgetting something from earlier: are you using well water or other iron contaminated fill water?

DE + polyquat + continuous filtration + backwash as needed + gradually chlorination = probably the best way to remove the iron.

[FormerBromineUser]

We used our well water for part of it; 1 tanker load of Chicago water and 3 tanker loads of municipal well water from a local water tower. You could see the brown tinge in the water as it was filling. Sent a video of the steps and pool on page 3 of thread. The white steps in the beginning showed the color. 4 quarts of HEDP probably didn't hurt.....

[FormerBromineUser]

I am proceeding with the plan, but I have a question that I don't want to confuse with tomorrow's test report. My pressure reading tonight after last night's backwash and addition of 2C DE had only gone up 3-1/2 psi. Not wanting to risk backwashing out any of my first 2C dichlor addition and confuse my results, I decided to first add the nightly 2C of DE and let it sit for a bit just in case the psi went up. 45 minutes later, my PSI had risen to 30! Could the DE have acted THAT quickly? The filter was also leaking at the top. I did a backwash and I am now down to 20-1/2. The backwash water seemed clear or maybe light grey although it was getting dark so it was hard to tell. It was definitely not dark orange like last night. I did NOT add more DE after backwashing, just the 2C dichlor.

[BigDave]

I don't think you need to add the DE nightly. Just when you backwash it out.

[PoolDoc]

What he said . . .

However, when the DE plugs, and pressure begins to rise, it can rise rather quickly to the maximum possible.

[FormerBromineUser]

After adding 2C dichlor at dusk.
PM:
pH 7.4
C 0
TA 190
CH 90
CYA 0
AM: same except I got 180 for TA

[PoolDoc]

Add 6 cups tonlght.

[FormerBromineUser]

After adding 6C dichlor and waiting an hour:
PM:
FC: 5.4
CC: 0.8
pH: 8.0
TA 200
CH: 90
CYA: 0

AM: (I did not get up at dawn but the auto-cover was closed)
FC 5.0
CC: 0.8
pH: 7.4 (but if I let it sit for a while it rises to 8.0 so maybe that was issue last night?)
TA: 200
CH: 90
CYA: 0 (but the mixture looked cloudier than last night)

[Watermom]

Read the pH when you do the test instead of letting it sit. Also, no need to test the CYA so often or you will run out of reagents. Once per week while you are using dichlor is probably plenty often enough.