First time testing - safe for kids to swim?

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gqueller

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May 25, 2011
12
Hi All -

I'm trying to wean myself off of the $125 / month pool guy and do it myself. We've just put in a SWG and VS pump in for our old pool, so there is a lot of tinkering ahead of me. I ran the SWG in superchorinate mode for the last 24 hours, but when I came home it said low salt, so I'm not sure how long it ran (and I need more salt). Here are the results my first tests:

28K Gallons

FC 5
CC 0
TC 5

Ph 8.2
Acid Demand 4-5 drops
TA 140
CH 800 (!)
CYA 95 (not sure I got this right, but it's close).

I'm going to go play with the calculators, but any initial suggestions? We've got kids visiting tomorrow and they want to swim, think it's safe?

Thanks,

Chris
 
From what I have learned the salt is nothing to worry about. If it is low it will just mean a bit harder water; salt should be around 2000ppm or a bit higher. Your pH, TA, and CYA seem off. Retest and report back, but you should be ok to swim. Salt content won't hurt anyone.
 
If your CYA is 90 to 100, then you should have a FC closer to 7 ppm.

Your pH is way too high at 8.2. The normal range for pH is somewhere between 7.2 and 7.8. 8.2 is hard on pool surfaces and will irritate swimmer's eyes. I would add acid to lower to 7.4. Additionally, that high pH coupled with the high CH means that your are at risk for scaling.

You can address the CH after the kids have come and gone, but that FC should come up and your pH needs to come down. You need to be vigilant about pH control with any pool, but especially with SWCG pools as the pH is constantly trying to rise in those pools.
 
gqueller said:
Thanks! I'll get some muritaic today. How long after adding acid can one swim?
Click to expand...
If you get things mixed up well by running the pump and brushing the whole pool, I'd say by the time you've finished brushing, it's safe to swim.

And pick up some liquid bleach, too. When those kids are done, dump enough in to get you up to 10 or so.
 
Leslie's sells a couple of different versions of that kit. It sounds like you have the K-2005 equivalent, which contains the DPD chlorine test, instead of the FAS-DPD chlorine test.

You can do the chlorine test with dilution by mixing equal amounts of pool water and chlorine free water (typically distilled water) together, doing the test on that, and then multiplying the result by 2. You can also do more extreme dilutions, but you quickly lose precision. Keep in mind that the DPD test can bleach out, sometimes showing very high FC levels as if they were zero.
 
About .5 gallon of Muriatic Acid later, the ph has improved. New measurements:

FC 7 (estimated, need the better kit)
PH 7.6
TA 130
CH 730
CYA 80
Salt 4750

Some of the change has to be variability on my part as I get better at the tests.

The next step is to lower the TA down to ~ 90, and the pool school post shows the acid / aerate cycle will do it. The only thing I'm confused about is it mentions that I can use the SWG to aerate, but doesn't explain how. I could also hook up a blower to the spa air line, or build one of the sprayers, I suppose.

It seems like what I really need to do is replace 50% of the water, but I really don't want to do that as I'm planning on getting it resurfaced at the end of the season... Plus, I just poured in > $100 in salt...

Also, I'm noticing small bubbles coming out of my return lines. But it only seems to be when the VS pump is running @ lower speeds, but I'm really not sure about that. Any cause for concern? Could it just be picking up air from the spa air line?

Thanks!
 

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If you only see the bubbles when the SWG is running that is normal, and that is what they mean by having the SWG aerate for you. The bubbles generated by the SWG will raise pH over time so check pH frequently and adjust as needed.
 
If you're gonna replaster next season just work on keeping the pH in the low 7's and you should be fine. Even if you get a little scaling it's going to be gone next year anyway.

If your CYA is close to 80 I wouldn't worry about it either. Your FC should be between 4 and 6 with a swcg and a CYA of 80.

Now get out there and go swimming!
 
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