Nasty stuff blown in with storm - how do I prevent it?

[Drew80]

This has now happened twice to me. My chlorine PPM is at about 5-10. My CYA is about 30. We leave town for 3 days and get a BIG rain. When we get back, the water is green and cloudy and my chlorine and CYA are gone and the water is full of ammonia.

Somehow the rain is blowing in enough stuff to overwhelm the chlorine, neutralize it all, and some kind of bacteria is eating all my CYA and converting it to ammonia. I know how to fix the problem (lots and lots of chlorine to mix with the ammonia), but I don't understand why this keeps happening to me. I've had pools before and never had this problem. We just built this pool in January, and with all the rain in central Texas right now, this has happened twice in the past month.

What am I doing wrong? What can I do to prevent this in the future?

 

[jblizzle]

Does not sound like you are doing anything wrong, just bad luck.
Can you cover the pool when you are gone?

Capture, cultivate, and sell the bacteria/debris as a CYA reducer

 

[mknauss]

Trying to manage a pool with a SWCG using a CYA of 30 is tough. I would suggest keeping your CYA closer to the recommended levels. And then make sure the SWCG is creating more than enough chlorine each day, even boosting it up some when you are gone.

 

[jblizzle]

Marty makes a good point. 30ppm for a SWG in TX is going to be tough.

 

[JoyfulNoise]

Are you getting soil blown into your pool or is rain runoff entering the water? Are you sure you have ammonia in the water (have you measured it with a aquarium test kit)? The bacteria that uses CYA can be found in soil, so keeping the pool clean is paramount to keeping bacteria out.

30ppm CYA is far too low for an SWG pool AND, contrary to popular opinion, CYA can be oxidized by chlorine and high UV levels. In my own pool, I can easily see a 10-20ppm loss of CYA per month during the hot and sunny months of the summer. So, if your running your CYA so low, then your SWG is not going to be able to keep up and you’ll eventually have an algae bloom. The only time TFP see’s folks using such low CYA with an SWG is when they are also using an ORP control system to dose chlorine. ORP probes need low CYA levels to function properly but that inevitably leads to an SWG running at 100% output all the time. I’m assuming you’re not using ORP control....

 

[Drew80]

Are you getting soil blown into your pool or is rain runoff entering the water? Are you sure you have ammonia in the water (have you measured it with a aquarium test kit)? The bacteria that uses CYA can be found in soil, so keeping the pool clean is paramount to keeping bacteria out.

30ppm CYA is far too low for an SWG pool AND, contrary to popular opinion, CYA can be oxidized by chlorine and high UV levels. In my own pool, I can easily see a 10-20ppm loss of CYA per month during the hot and sunny months of the summer. So, if your running your CYA so low, then your SWG is not going to be able to keep up and you’ll eventually have an algae bloom. The only time TFP see’s folks using such low CYA with an SWG is when they are also using an ORP control system to dose chlorine. ORP probes need low CYA levels to function properly but that inevitably leads to an SWG running at 100% output all the time. I’m assuming you’re not using ORP control....

There's a little bit of brown stuff in the pool right now, but I don't see how it could be soil. The pool is surrounded by crushed rock with limestone pavers - there isn't any exposed soil for about a 3' perimeter. Could that bacteria live in the trees?

I haven't actually tested for ammonia, but it gives off the typical signs - foaming, funky smell, and immediately neutralizing all chlorine. If it's not ammonia, it must be some other positive ion.

I'll bring my CYA up this time around.

 

[JoyfulNoise]

There's a little bit of brown stuff in the pool right now, but I don't see how it could be soil. The pool is surrounded by crushed rock with limestone pavers - there isn't any exposed soil for about a 3' perimeter. Could that bacteria live in the trees?

I haven't actually tested for ammonia, but it gives off the typical signs - foaming, funky smell, and immediately neutralizing all chlorine. If it's not ammonia, it must be some other positive ion.

I'll bring my CYA up this time around.

That could just be algae and bacteria you’re killing. You can get chloramine type odors from any kind of “green” pool but that doesn’t necessarily mean you have ammonia. Also, a green pool will consume FC at a very fast rate initially as it all gets used up killing pathogens and oxidizing waste. SO the only definitive way to know if you have ammonia is to test for it.

I would suggest that if you’re going to use your SWG for chlorination, then you need to follow the minimum guidelines in Pool School for CYA and SWG pools.

 

[JamesW]

Bacterial conversion of cyanuric acid to ammonia will result in a noticeable drop in cyanuric acid, high CC levels and ph drop on adding chlorine.

 

[Drew80]

Bacterial conversion of cyanuric acid to ammonia will result in a noticeable drop in cyanuric acid, high CC levels and ph drop on adding chlorine.

I have 0 CYA as of this morning and I had 30 before the rain, so that seems like a noticeable drop. I haven't tested for CCs during this process, but after adding enough bleach to bring my FC up to 20, it would drop back to 0 within minutes. I had to do that 4 times to get it to stabilize. Also, lots of foaming, and I don't think that's from killing algae.

It may not be ammonia, but there's something floating in my water that's not typical.

 

[jblizzle]

Did your bleach have any additives in it?

 

[JamesW]

Check for CC, pH and TA.

1.0+ CC and dropping pH and TA can confirm ammonia.

 

[Drew80]

Did your bleach have any additives in it?

No. Pure 10% hypo.

 

[Drew80]

Check for CC, pH and TA.

1.0+ CC and dropping pH and TA can confirm ammonia.

I've neutralized it all at this point, so the CCs are near 0. pH and TA are definitely lower than normal

 

[ajw22]

Run your pump longer and up your SWG output at least during storms. Pump and SWG running during the storm will tend to keep the water at uts best while junk is blown into it.

 

[Katodude]

A little trick that I have started to do when I go away for a few days is to put a couple trichlor pucks in my solar breeze. I keep my CYA on the low end of the SWG spectrum (around 60, and in the summer it drops a lot too). So the pucks give me the added benefit of a little extra chlorine in the pool, keep the PH down while I am away, and gives me a little boost of CYA. All things I am looking to do in the summer.