ok i finally tested my swamp...i mean pool...with a dpd test

[fog80]

Here are my results. (i have a 25k gallon IG concrete (i think) pool)

FC-0 (as expected)
TC-0 (as expected)
CC-0 (as expected)
PH-8.0
Alk-60 ppm
CYA- >30 (i had to fill the tester thing all the way to the top and I could still see the dot. I believe I have zero because I refilled the pool last year and used only bleach all season. I was wondering why my chlorine wouldnt remain steady, but now i know the reason)

First thing I did was clean my DE filter, put it back together and put 6 pounds of DE through the skimmer.

Then I bought a five pound bottle of CYA and put the whole thing in.

What should I do next? (chlorine first or adjust the ph)

[waterbear]

bring your alkalinity up to about 80-100 ppm with baking soda and then adjust your ph into range with muriatic acid. wait 24 hours after adding baking soda and test alkalinity, when it is in range adjust pH

[Watermom]

Go ahead and get some bleach in there or you will have a green pool in no time. Then you can work to get the ph down to 7.4-7.6. Don't retest the cya for about a week to be sure and give it plenty of time to dissolve in your filter. Also don't backwash during that time period or you will just be throwing the cya out.

Watermom

[waterbear]

I could be wrong on this but wihtout a good alkalinty buffer system in place wouldnt the bleach cause the pH to bounce up? Seems like it would make sense to get that done first. Also the bleach is less active at higher pH becuase there is more hypochlorite ions and less hypoclorous acid present.
If it turns green a shock dose of bleach should clear it right up.

anyone got any ideas on this?

[fog80]

ok im gonna dump about 8 pounds of baking soda in there tomorrow morning to get my alkilinity to about 80 ppm.

Then I will put about 50oz of muriatic acid.

after that i will probably add the bleach.

can all this be done in one day, or do i have to wait?

[waterbear]

I would wait about 24 hours after the baking soda and test before putting in the muriatic acid...you can dump the bleach in right away. It will probably make your pH climb a bit more though.

[CarlD]

Wow!

I'm confused! Why did you throw all that junk in your pool????

Your CYA was greater than 30, your FC was 0, and your pH was 8....

So you added more CYA??? Before the chlorine??? If you have an algae bloom and no chlorine, you will have discovered the OTHER way to get rid of CYA--home-brewed swamps will consume CYA.

What I would suggest: Add lotsa bleach to get your FC up to at least 15. Add muriatic acid to get your pH down to 7.3-7.8. Then check your FC 3x/day and keep it at 15ppm. Run your pump and filter 24/7 and vacuum to waste every day.

Only chlorine will kill the algae. Always get your pH and FC set first.

[Watermom]

Yep - As usual, Carl and I agree. That is what I also advised further up in the thread. Keep it simple. PH and FC first. Other stuff later.

(By the way Carl, I think fog80 meant to say that his cya <30 instead of >30 because further into his post he says he thinks he has none.)

Watermom

[CarlD]

No WONDER I was confused. In that case I would have about 3 or 4 floaters loaded with Tri-Chlor tabs set to the widest opening. They will push chlorine, CYA and lower pH all at once...PERFECT for what he needs.

[duraleigh]

Fog,

CarlD misinterpreted your post, I think. (You used the "greater than" symbol but intended to use the (<) "less than" )

What you've done to this point is harmless enough but you need to get some Cl in the water as well.

Yes, it can all be done in one day. There'll be some differing opinions on that....many use a more careful approach. If you have tested ACCURATELY, however, you will be fine, IMHO.

Waterbear brings a good point about the Cl boosting your pH but it's been my experience the Cl will have negligible effect. I think it's about pH 11 or so and you're just not (or SHOULD not be ) adding enough to significantly modify the pH of a 25,000 gallon pool.

Dave S