Chlorine getting chewed up. Algae?

Jump to latest Follow Reply
Drew80

Drew80

0
Feb 26, 2013
337
Austin, TX
We were out of town for a few days and got a massive rain. When we got back, the pool was cloudy but didn't have that distinctive green algae color so I wasn't sure what was going on. My CH is about 400, my pH is around 7.2, and my TA is 200.

I added some muriatic to bring down the TA. I also dumped two full gallons of 10% bleach in (8,750 gallon pool) about an hour ago and I'm still getting a reading of 0 for FC and very high for TC. Do I just have a huge algae bloom? Could it be mustard?
 
Algae?... perhaps. Or with all the rains lately perhaps something washed "into" your pool from local run-off. Either way, a SLAM Process is your best bet. But you will need to have plenty of bleach on-hand to keep the FC at the proper SLAM level as noted on the [FC/CYA][/FC/CYA]. Remember to maintain that SLAM until you pass all 3 criteria.
 
Zero FC but high CC? Hmm, what is your current CYA level and what was your FC reading when you first tested after you got back?

Also why did you add MA when your pH was 7.2? You don't want you pH lower than 7.2.
 
If your CYA dropped a lot and you're getting a bunch of CC, you probably had bacteria eat the cyanuric acid and convert it into ammonia.

You shouldn't have added the acid. Ammonia is NH4+.

Chlorine oxidizes the nitrogen to nitrogen gas and leaves all the hydrogen ions behind.

Hydrogen ions are acid, so they lower the pH.

If you have ammonia, you should see a ph drop as you add chlorine to get rid of the ammonia.
 
Maybe need to take step back and reverify the facts provided. FC = 0 but TC is very high. Please confirm.

TA = 200? That just didn't happen in a few days or rainfall. I just had 6 inches fall over past couple days and TA barrely changed. Confirm200 and how long?

With pH of 7.2 that's already on the low side, confirm that too. You def shouldn't be adding MA to lower your TA or your pH is going to really be in trouble.

Also post what your CYA is, it must be 0. Again, for how long at the current level? It wouldn't wash out by rain, perhaps ammonia in water, but don't feel that get high so quickly.

Have you tested for phosphates? Too high a level becomes a buffet for algae.

Lastly, what was your SWG output set at while you were gone and how many hours/day?
 
I added more bleach and let it run for another 2 hours with no change in appearance. Here are my latest measurements:

FC - 6
CC - 1.5
CYA - <20 (I have no idea what happened to it)
TA - 180
pH - 6.8

I'll answer comments in order.
- I tested this morning with a quick strip because I was in a hurry, but these latest values are with the TF100
- The FC was zero when we got home
- I added MA because I've been fighting TA since I first built this pool. It was brand new in March, and I haven't been able to keep the TA down. It started at 350 (Austin water). I've gotten it down to 100 at times, but it always creeps back up along with the pH.
- I don't have a phosphate test, but I added two capfuls of phosphate remover this morning.
- The SWG was at 40% and it's been running for 6 hours a day. I've been experimenting with time vs SWG level and this seemed to be working perfectly before the big storm

Before all of this happened, I was running at a CYA of around 60 and FC of about 4. As others have said, something must have eaten the CYA because it's gone.

I'll also note that the entire back yard is covered in a film of black gunk from this storm. No idea what it is, but maybe that has something to do with the pool problems. We have a TON of trees around our pool - maybe something blew off of them?
 
You will need CYA. If your pool is now holding FC add 30 ppm worth of CYA powder using the sock method. Follow the [FC/CYA][/FC/CYA] based on the 30 ppm CYA being in the water (do not have to wait to test for it) and SLAM Process
.
 

Enjoying this content?

Support TFP with a donation.

Give Support
Had you been circulating the spa during the prior additions of chlorine?

Foaming typically means you either are using a bleach with additives (though you say you have 10%) or you have ammonia. It will foam and stink at first.
 
True. But you stated earlier you had FC of 6 ppm. If you have ammonia, your pool will not hold ANY FC. It is consumed immediately.
 
I’d suggest you completely and totally ignore your TA. Don’t even test for it. Manage your pH and the TA will fall in line eventually.
 
Drew80 said:
And is there anything I do about that other than adding a ton of chlorine? I added about 2x shock level last night, the water foamed like crazy, but it didn't get any clearer.
Click to expand...

I do not understand. If your pool will hold 6 ppm FC, then you have no ammonia in the water.

The pool will not clear instantaneously. You must SLAM (The M is for Maintain) for several days to several weeks to clear your pool.
 

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply