Added too much acid

[Fast411]

I pulled the cover off the other day and my pool was green with stringy green algae everywhere. I don't close the pool. I just adjust the SWG down and let it go. Somehow, probably my goof, my SWG got turned off. Long story short, my pool wasn't clean and clear when I took the cover off.
So I did a test with the TFP kit.
3/17/2010 FC2 CC0 TC2 PH8. TA50 CH70 CYA20 Salt 2100 Temp55

So I whipped out my pool calculator and went to work to shock it. First I added enough salt to get back to level(swg off). Then, well, I didn't adjust TA in the calculator before I started, so I added 3qts of acid instead of 58 oz. I then added the chlorine to get to shock level suggested by the online pool calc(not the ipod one I used before) and that is when I noticed the error.

Q:Will the rise in chlorine negate the additional acid? Should I worry about it? I have metal issues, so i figure the low ph might be good while shocking.
edit: I am guessing by using the pool calc backwards that my ph is around 6.8-6.9. That is no biggie anyway, right?

 

[JasonLion]

Having PH down to about 7.0 is fine. Below that it is best to raise the PH up to at least 7.0 as soon as practical. Keep in mind that the PH test will read higher than actual when the FC level is above 10.

I also noticed that your CYA level is way too low for use with a SWG, recommended CYA level is 70 to 80 for use with a SWG. Best not to raise it quite that high till any possible algae is gone.

 

[frustratedpoolmom]

Actually it is. What is your FC now? FC over 10 will cause the PH to read false high, and when the FC drops down so will the PH.

Now that you have adjusted the chems, can you do a new set of results for FC CC PH and TA and post them here.

You don't want the PH that low if that's what it is.

P.S., on an unrelated note, please remove the info about the "RIP motors", signatures are limited to 5 lines of text. Thanks!

Jason and I are typing at the same time...

 

[Fast411]

I adjusted the sig....sorry it has been that way since I joined and was apt to my pool problems/postings at the time.

@frustrated pool mom
The initial FC and ph readings were before the shock. I shocked to 11, after 1/2 hour it was FC6 CC2, I added back to FC11 before I read your post. I did not test the ph, because I knew it would read wrong with high FC. I will do another full test on the next cycle in an hour. I am in the shock cycles now for algae and I am guessing I can test my ph when I test the FC drop, because the FC will be lower.

@Jason
I am going to address the CYA later. Based on your other posts I decided to wait until after the algae treatment.

Thanks to you both

 

[duraleigh]

Fast411,

Sounds Like FPM and JasonLion have you on the right track.

I know you didn't ask this question or ask for comments but I noticed your filter is pretty small for your pool. When you're up and running in the summer, how many hours daily do you run the pump to keep the pool sparkling? How often do you find you have to backwash?

I'm not being critical of the equipment match but I am interested in your experience with it's performance.

 

[Fast411]

@Dave Last year is the first year that I didn't run it 24/7. For the first three years it was sparkle city and low mtx. I ran it about 8 hrs a day when I was cutting down last year, but I was dealing with metal issues, so I had to run it more sometimes.

I backwash once a month, it never gets over pressure unless I use a fliter aid. My pool has two skimmers two returns.

 

[Fast411]

Well the FC is 11.5, CC shows 0. I did a quick ph anyway, it was about 8.something, the color of the top block. I am just going to keep it at shock level now.

Any bright green goop is gone, the water is now low vis/cloudy, so I am guessing the shock is working. I don't think this algae started until a couple weeks ago when the weather warmed up real fast So, maybe I can get ahead of it.

 

[duraleigh]

Sorry, forgot to ask....What has been your clean filter psi? Have all the pumps been pretty close in psi?

 

[Fast411]

Ok, so it is less cloudy but the FC held overnight at 11, and at that reading pH was 7.8. I did three test for CC and got 0,.5, 1.0, so I am not sure where I am there, each time the FC was the same. The algae appears to be collecting as brown dust on the pool bottom. It is in blotches or in drifts at the seams. So, some of the water clearing has to be the settling of what I brushed up. I guess I will vacuum this afternoon.

Can 55 degree water affect the testing? Should I let it sit in my house for 30 minutes then test at room temp?

 

[JasonLion]

The CYA test is the only one that can be affected by cold water. FC and PH should be measured right after taking the sample. TA and CH don't care if you wait or not. CYA should be warmed to room temperature before testing (if the water is cold).

 

[Fast411]

The reason I asked about the temp when doing FasDPD is that I am getting inconsistent results.

I wash out the cylinder, add the crystals and swirl. Not all of it dissolves but it turns bright pink. I add a drop of reagent and swirl each time. On drop 20 it turns clear for a microsecond, on 21 a little longer and on 23 it goes clear for good. But, if I wait about 10 seconds, the time it takes to move to the CC test, it turns slightly pink tint again. After recording my number, I played with this and seems I could keep turning it pink just by waiting longer and /or warming it in my hand. That is why I asked.

I took my measurements at the first totally clear moment that held for a few 4 or 5 seconds

 

[JasonLion]

What you describe can happen if you do the test too slowly or the CC level is relatively high. If it stays clear for ten seconds then you are done with the FC portion of the test, even if it turns pink again after that. Likewise, if you leave the sample sitting after the CC portion it will usually turn pink again eventually.

You want to do the test without pausing, swirl constantly and add drops perhaps every two seconds until right near the end. As you approach the end you need to slow down a little so you don't miss the moment when it turns completely clear.