Need help w/test results

[The Mermaid]

OK, here is a little background. 28ft AG pool w/paper cartridge filter. The pool is old. We had a piece of the plumbing hardware break a couple of weeks ago and we were not able to find a replacement. So hubby and I decided next year we would just replace the pool. We planned to dismantle everything this fall when the weather got more tolerable. But now we've had a change in plans. We've decided to keep using this pool for a couple more years, but since the pump hasn't been running, now we've got algae. Hubby figured out a way to repair the original problem so now we have the pump and filter going nicely, but trying to get rid of algae.

I figured the first thing to do was add bleach to shock levels. I've always heard that cya levels don't fluctuate much if you're not adding cya, so I added what I thought was enough to take levels up to about 15ppm with CYA of about 35. This is how it tested 2 months ago. I let that circulate and tested.

FC = 15.5
CC = 0.5
TC = 16.0
PH = 8.2 (could be higher that is the max on my test)
TA = 90
CYA = 0 (WTH????)

So I want to get rid of algae and get my water balanced again. Temperatures here are in the 70s in the daytime right now and drop down into the 50s and 60s at night.

I know my FC is a bit high, but the pH is really high!!! Also, how did my CYA drop from 35 to 0 in just 2 months? Evaporation and rainwater???

What do I do next? Just maintain shock level and filter until algae is gone? Should I be adding acid to lower the pH, or wait until the algae is gone? I figure if I throw in a few pucks to get my CYA back up, my pH will get lowered anyway, so maybe I ought to add pucks before fiddling with pH????

Any help is much appreciated. Pool holds about 22,000 gallons. It's above ground but has a dished out bottom that is deep.

[duraleigh]

Your post is a little confusing. How old are the test results?

[The Mermaid]

OK, sorry, I know everyone here is a stickler for details, but maybe I included too many.

The test results posted are from yesterday after we got the pump running. Would like to clear the algae. The pH is high and the cya is low. My question is, in what order should I correct these things? Get rid of algae first, then increase cya, then see if the pH needs to be tweaked? Or do I need more stabalizer in order to efficiently fight the algae? I'm adding cya with pucks which is slow. I was shocked that my cya was 0 when 2 months ago it was 35.

[aylad]

The algae is probably what broke the CYA down...that tends to happen when there is a bad outbreak. For now, get the chlorine up to 12-15, and keep it there by retesting and adding more 2-3 times daily until the water goes to blue/cloudy. While you're doing this, keep the pump running 24/7 and brush the pool at least daily. When the water goes to blue/cloudy, continue to run the pump to get the dead algae filtered out (this may take several days), but watch the pressure on your filter and rinse cartridges as needed. After the algae is cleared up, then add your CYA.

Janet

[The Mermaid]

OK, thank you very much. I thought that's what I should be doing, but have never had algae before (thanks to BBB) and just wanted to make sure.

[duraleigh]

Mermaid,

Simultaneously with Janet's advice, I would get your pH down around 7.2 - 7.5. You'll need muriatic acid to do that. Start with a quart and retest in an hour or so (pump running). You'll probably need a second quart.

[The Mermaid]

Duraleigh,

I've got some tri-chlor pucks dissolving in there now (for the stabilizer). I know it will take them a few days to completely break down, but they always lower my pH and raise cya. I was trying to avoid lowering pH now, then having to raise it again after the pucks dissolve. Do you think the pH is really that urgent right now? I honestly have no idea. What sort of bad stuff does high pH do? Does it happen quickly?

Melissa

[The Mermaid]

Oh and also.... I was trying not to add acid and chlorine at the same time b/c of poisoneous fumes. It seems I'm adding chlorine VERY frequently right now, so if you still recommend acid for pH, how much of a time lapse should there be in between chlorine dose and acid for safety purposes?

[duraleigh]

Adding acid and chlorine one right after the other will produce no adverse result.

Get your pH down now and your Cl will be noticeably more effective.


Do you think the pH is really that urgent right now?Yes. Lowing pH with pucks is a little too slow for what you need to do. Leave the pucks in there if you like but you need to get your pH in a range you can test. You don't know how high it is.

[The Mermaid]

OK, thanks a bunch!!! I went ahead and added some acid last night and this morning pH tested at 7.2. I'm still maintaining FC at shock levels although the water is no longer green. It looks blue now but still a bit cloudy. I expect it will take a little time to filter out all the small stuff. I'm just going to continue to maintain FC and brush frequently and rinse out filter when pressure goes up a bit.

Do you think the pucks will eventually raise my cya up to an acceptable range? Or should I do something more aggressive? Is there a liquid stabilizer that I can add?

[duraleigh]

Sounds like you've got a good plan. The cloudiness is mostly dead algae and, you are correct, it will filter out over the next few days or maybe sooner.

Yes, the pucks will slowly get your CYA to the correct level. At this time of year, (since you won't have a big chlorine demand) that would be an acceptable way get the job done........two caveats......It will also lower your pH (slowly) and, if you don't monitor the CYA level, will continue to add it until you have too much and then you must drain and refill to get rid of it.

Keeping those things in mind, pucks will work nicely for what you want to do. Don't plan on using them next Summer for the above reasons.

[The Mermaid]

OK, thanks again. You've been a great help. I normally do not use the pucks unless my cya gets a little low. I normally like to keep it around 35-40. Probably a couple of times total in the summer, I end up having to add a couple of pucks to bring it back up, but that's it. Since my cya tested at 0, I don't think the few pucks I have in there now will raise it too much. In fact, I expect that I may need to add a few more, but will definitely do it slowly. Thanks again for the great tips. The pool is blue again and I'm a happy camper.