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

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)

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

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

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?

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?

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.

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.

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

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.

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 :D ) adding enough to significantly modify the pH of a 25,000 gallon pool.

Dave S

In my pool, adding bleach does nothing to affect the ph level. In other pools it seems to somewhat, but that has never been the case for me.

Watermom

thanks for the help guys.

just to clear up a few things.

i added 5 lbs of cya to a pool with an initial reading of zero.

then i added 4 lbs of baking soda to bring my alkalinity to 100 ppm

i then added 5 lbs of cal-hypo shock powder

ive been running the filter non stop for two days. my de filter pressure rises pretty quickly and then i have to bump the filter and restart it to get the pressure down again (my bump handle is broken so im doing the best i can with that)

i dont want to backwash yet because i added the cya and fresh de a couple days ago.

the water went from dark green to semi-blue overnight. I cleared out most of the leaves off the bottom today and just added 3 1.42oz jugs of clorox and will keep the pump running tonight.

for some reason when i checked the water ph last night before adding the chlorine the ph level went down to 7.2 from 8.0 and i didnt add any muriatic acid at all.

Even though the baking soda is alkaline it introduces a buffer system into your pool. Without it the pH can bounce all over the place. Perhaps when you took your previous reading it was during such a bounce and now that the water has buffer reserve a truer pH reading is what you are seeing... Also the CYA, as it dissolves, can temporarily lower the pH. (It does it in my pool) It is acidic.

Quote:

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Originally Posted by waterbear

Also the CYA, as it dissolves, can temporarily lower the pH. (It does it in my pool) It is acidic.

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that must have been what did the trick!

anyway, my pool is really starting to look good again. I just need to keep brushing the walls and the floor and get the rest of the gunk out.

thanks for all your help. I will post some more current results tomorrow.

ok as of tonight my pool readings are:

fc-15
cya-45
ca-250
ph-8

the chlorine is pretty stable because i put in chlorine almost 24 hours ago and its still showing 15 (i think its higher but my kit will only let me go as high as fifteen)

the water looks pretty clear now, and my cya readings were up so i backwashed the de filter, bumped it, and backwashed some more and then added 5 lbs of fresh de.

i still have some dots (algae?) on the walls that wont go away though.

Lower you pH to 7.3-7.5 and the chlorine will be FAR more effective--and may just get rid of those dots.

BTW, you need to brush your pool everyday when you have an algae bloom--knocks the algae loose where the chlorine can get at it. That WILL get rid of those dots. Forgot to mention that-still rusty as I haven't even begun the pool opening process.

Quote:

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Originally Posted by CarlD

Lower you pH to 7.3-7.5 and the chlorine will be FAR more effective--and may just get rid of those dots.

BTW, you need to brush your pool everyday when you have an algae bloom--knocks the algae loose where the chlorine can get at it. That WILL get rid of those dots. Forgot to mention that-still rusty as I haven't even begun the pool opening process.

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thanks. i'll add some muriatic acid tonight.