Stabilizer Mystery

[PoolDoc]

If you've got 3 weeks, and your filter is functioning reasonably well, you should be fine.

Grey is dead; green is live. (tho, I think you'd worked that one out ;-)

RAISE THE PH!

Adding chlorine to ammonia in a HIGH ph solution produces monochloramine, which is GOOD at penetrating clinging algae. Free chlorine is not. Monochlor is what Yellow OUT leads to, IF you follow the directions. It does work; it just leaves a mess to clean up. But you've ALREADY got the mess, so no worries there.

But, if you don't raise the pH, you'll tend to produce di- and tri- chloramines which are stinkier and are NOT good for anything that I'm aware of.

20 ppm is about right. If you brush and stuff, it will drop very quickly. But, you should probably stay out of the "brown" OTO range. I think 20 is dark dark orange.

Ben

[CarlD]

I think I see something: Your CYA didn't rise because it takes 48 hours to a week for the CYA to dissolve properly...and if you've been vacuuming to waste you may WELL have vacuumed up and out the undissolved CYA particles.

You've got a gunite pool. If it were me, I'd get a 5 gallon carboy of 12.5% liquid chlorine and dump in 2.5 gallons. That should raise the FC by about 30ppm, which may just make a dent in the algae. 8 hours later, I'd check FC again, and if it dropped, I'd dump in the rest of the LC. Gunite/concrete/plaster can tolerate such high levels, unlike vinyl.

When you use the OTO, are you diluting it with steam distilled water? If not, look up the Shot Glass method. Mix one shot of pool water with one shot of distilled, and you can double the readings. Two shots of distilled to one shot of pool water and you can triple the reading. 3 shots distilled, quadruple. Beyond that you will probably be losing accuracy.

[TonyPH12345]

CarlD: Walmart is less than 300 yards away from my front door. 1.5 Gallon bottles of 6% bleach at $2.00 per bottle is a lot more convenient than to find a 5 gallon carboy of 12.5%

My filter doesn't have a setting for Vac-to-Drain; it still recirculates. So I don't think that's where my CYA went...

Thanks for the suggestion!!

[PoolDoc]

Tony, you're right to remember that high chlorine affects phenol red . . . and in spite of having warned about that many times, I was forgetting it. But I lucked out, and still gave good advice. High chlorine makes pH appear high, not low. If you are still reading low, (7.6) I think it's prudent to assume you are.

In any case, the higher the pH, the greater the propensity to form monochloramine preferentially over other species. (So, add borax!)

Ben

[chem geek]

In any case, the higher the pH, the greater the propensity to form monochloramine preferentially over other species. (So, add borax!)

Just FYI: monochloramine forms almost immediately (in less than a minute in pools with recommended FC/CYA amounts) when chlorine combines with ammonia and this happens at all pH levels. Higher pH levels tend to produce more trihalomethanes (e.g. chloroform) when chlorine oxidizes some organics (those that have or end up with methyl ketone groups) while lower pH levels tend to produce more nitrogen trichloride from multiple substitution with ammonia and partial oxidation of urea (i.e. it is a disinfection by-product). Generally speaking, at the low active chlorine levels in pools with CYA and the low bather-loads in residential pools, I wouldn't worry about either.

[CarlD]

Tony, If WalMart is 300 yards away and 1.5 gallons are $2, go with it. It doesn't matter if you use Walmart 6% or carboys at 12.5%, as long as you get your FC where it belongs and keep it there. I like the carboys because I can get them easily, easier than bleach and the price is generally good. Plus the jugs are reusable like deposit bottles. But the important thing is you are using sodium hypochlorite. In that, there's no difference between bleach and Liquid Chlorine.

As for CYA, it still takes 2-7 days for it to dissolve and affect the reading, so you cannot expect immediate results.

CarlD

[TonyPH12345]

Heheh... With as much NaClO as I've dumped into the pool in the last five days (I'm up to about 12 gallons so far) I will probably end up with a significantly salt-water pool!

But things ARE improving. The algae deposits continue to oxidize and turn brown and brush away. I've removed the Polaris' bag because it's not doing much good other than to clog itself up with slime, but the tail sweep is helping somewhat, and it's agitating the junk on the bottom back into suspension in the water to draw into the filter...

Pressing on...

[TonyPH12345]

Yeah, I didn't mention that. I'm titrating the pH up to 8.0; I've never used Borax as pH increaser before; only used Soda Ash before. So I don't know what the dosing should be and I don't want to over-shoot it...

Does high chlorine affect Phenol Red test? IOW, can I trust what I'm seeing on the Ph test when my chlorine > 15?