How to raise CH and when is it safe to swim ?s

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R

rlsnights

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Sep 9, 2008
79
What's the best way for me to add the stuff to raise my CH to my plaster pool?

How soon is it safe to swim in the pool after I add it?

How soon is it safe to swim in the pool after adding muriatic acid to lower pH?

I can't figure out why my pH keeps going through the roof. Any ideas?

TC 8
FC 8
pH 8.2
TA 120
CH 160
CYA 50

Patricia
 
You can raise your CH by adding calcium chloride to your pool. Most pool stores should have it. I have heard that the deicer that you can find for sidewalks and such is virtually, if not exactly the same thing. Check the ingredients on the label prior to using.

If you have some bags of Cal-Hypo sitting around, you can use that too. Just keep in mind that it adds to your chlorine as well.

If your pool has good circulation, it should be safe to swim after about 30 minutes to an hour after chemical additions. Brushing can help speed up the process. The rule for my pool is 30 minutes after I add MA.

How new is your pool? Plaster curing during the first year of a new pool being open can drive pH up pretty continually.
 
I agree, also sources of aeration, like an attached spa, waterfall, fountain, etc. can also drive PH up. As you add muratic acid to lower it, over time you're TA should drop as well, and then you will see the PH become more stable. For people experiencing PH rise, the recommended level for TA is 70-90. Those who don't want to wait for the TA to come down on it's own can lower the TA faster thru the Acid/Aeration process. You can read about that in Pool School.
 
Our pool was replastered 2 years ago this spring so I don't think that's it. Our TA is a little on the high side but my attempts so far to bring it down haven't done much.

We don't have a waterfall or fountain. I have a bunch of kids swimming in it today so maybe that will help a bit. I told them to splash as much as they wanted and topped off the pool before they started. So far they are doing a good job of getting large amounts of water on the deck. :goodjob:

Could organic debris like leaves and pollen bring the pH up quickly? We've had a lot of wind plus the cottonwoods in the nature area are blooming so we're getting a lot of gunk in the pool. I'm having to clean it 2-3 times a week.

Would the low CH be contributing to the rise in pH?

Patricia
 
12 % liquid chlorine from the pool store. I figured out the cost was pretty much the same and I had to deal with a lot fewer bottles than buying regular bleach.

I just added about 4 # of calcium chloride which is probably not nearly enough but I didn't want to go too far in the other direction.

I'll check the water again in about an hour and post the numbers.

Patricia
 
New numbers

TC 8
FC 8
pH 7.5
TA 110
CH 220
CYA 50

Added more calcium stuff just now - should bring the CH up to around 260.

I think I am going to scream. :grrrr: :hammer: :rant:

I'm pretty sure the black algae is back in the shallow end of the pool. I was checking the pool after the kids left and adding the calcium. There are 3 places with black streaks/spots (just big enough to see clearly through the water) where we had them before.

So I had my son scrub the dickens out of them and all the space around them with the wire brush. He's not big and strong enough to sweep the whole pool and my partner's not home tonight so that is the best we can do for tonight. I'm going to raise the TC up to 30 tonight - if I have enough chlorine on hand. Whatever I have I'm putting in the pool.

I'm a little worried about the pH though - it keeps going up and I know I can't really get a good measure of it when the TC is really high.

Should I drop the pH to 7.2 before raising the TC levels?

Patricia "just shoot me and get it over with" the pool fool
 
Sorry to hear about the return of the black algae.

rslnights said:
I'm a little worried about the pH though - it keeps going up and I know I can't really get a good measure of it when the TC is really high.
Click to expand...
Don't test your pH when your FC levels are above 10 because it will read a false high.

Your pH of 7.5 is perfect and I would leave it there.

rslnights said:
We don't have a waterfall or fountain. I have a bunch of kids swimming in it today so maybe that will help a bit. I told them to splash as much as they wanted and topped off the pool before they started. So far they are doing a good job of getting large amounts of water on the deck. :goodjob:
Click to expand...
A lot of children doing a lot of splashing can be aeration.
 
Patricia, with BA it's not really necessary to shock, just keep the FC slightly more elevated than normal - it's the wire brushing of the spots that is the essential part, sometimes several times a day- to keep the heads nocked off so the chlorine can kill them. In your case I would keep your FC up above 10 and just keep brushing. Not necessarily the entire pool, just the areas where you are seeing the spots. Keep the FC at that level for a few weeks, and combined with the brushing that should keep them at bay.

What is your pump run time? Are there returns in the areas where you see these spots appearing? I'm wondering if you are getting "dead spots" in your pool water which allows them to take hold....areas where if the pump is off, and the FC in that particular area gets used up, or the circulation is poor...anyway, pump run time/schedule....we'll get this figured out for ya!
 

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We have a pretty old pool (circa 1960's) and there are only 2 return jets. There is no way to angle or direct them. So I would not be surprised if this is part of the problem.

Is there any way to deal with this besides ripping up the decking and changing the whole system?

Patricia
 
I am sure you can find some kind of fitting that will allow you to install return jets that can be aimed. Most pools have standard threaded return fittings. Normally, you should be able to unscrew the current fittings and install new ones.
 
I am really scratching my head here. Just re-tested the water and here's the results:

FC 10
TC 10
pH 8.2
TA 110
CH 190
CYA 50 (didn't retest this but it's been stable at this number for a while)

I'm assuming the pH is high because the FC is at 10. But according to this test my CH actually went DOWN from 220 to 190 after I added another 4 # of calcium hardness stuff.

Maybe I'm doing the CH test wrong somehow. I redid it 3 times just now and got two different numbers - first and last time it was 190 and the middle time was 220. Is it normal for you to get that much variation in the results? When I do this test using the FAS-DPD test kit the water turns pink (not red like it says in the instructions). Then as I add the reagent I get little flecks condensing in the water. I judge it finished when it turns light blue (w/little flecks) and doesn't get any darker with an additional drop of two of reagent.

According to the label, the CH should have gone up to at least 220 from 160 when I added 8#.

Patricia
 
It helps to do the CH test slowly, swirling for 15 to 20 seconds after each drop. That should help the end point be clearer and the results to be more consistent.

I agree, the PH test should be ignored until FC is below 10.
 
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