PolyQuat and Shocking with Chlorine

[Jakebear]

Since my pool is in limbo right now I can play and see what happens. I’m waiting for the temp to drop per Carl’s recommendation so I can close it. The FC is 5.0 right now with no algae.

I’ll add the recommended dose of PolyQuat 60 and let you know what things test at in the morning.

Edit: I forgot to mention -- the pool is completely covered with a mesh LoopLock cover ~ 90% shade, about 2 feet above water level.

[Jakebear]

Just checked FC down from 5.0 to 3.8ppm after 19 hours of circulating. Combined is .2ppm.

I used my Peristaltic Pump to inject the diluted Quat (1 gal h2o) into the return stream. That took about an hour since it only pumps 20gal/day

[Jakebear]

Another 30 hours have past and the Free Chlorine is down to 2.8 ppm and just a hint of CC (FAS-DPD barely pink) I'll call it .2 but if I could have used a half drop that probably would have done it. Also noticed pH is up a bit to 7.7 from 7.5 before the Quat.

I will begin injecting 6% Bleach when the pump come on (very early morning because of the frosty conditions). Anticipated (calculated) increase is 2.5 ppm based on injection rate and run time --- We'll see.

[CarlD]

Well, I just finished closing my pool today. I had my FC at 4, then added 48 oz of PolyQuat to my 19,200 gallon pool. FC dropped to 0. I then shocked it up, and, today, when I closed, FC was 13.5. I used Liquid Chlorine.

[haze_1956]

My understanding is that Polyquat is a essentially a Non-foaming Detergent.

I have read posts that recommend lowering chlorine levels before adding it when dealing with algae,

And some posts have recommended high chlorine to clear foaming in the pool.

So the question is, does chlorine break down detergents?
.

[CarlD]

I don't know about the last--or the first.

PolyQuat should NOT be used when fighting algae. By then it's too late and you must maintain consistently high shock levels of chlorine to do the job.

Since the only algaecide I use is PolyQuat, I never have had a foaming issue.

I know it sounds crazy to say this, but the simpler you go with your pool chemistry, ie, B-B-B, and the more relentless you are about REGULAR (daily) testing of your water's chlorine and pH levels, the less trouble you'll have. It's easy. It's quick. It's cheap. It works. Why go any other route?

Because I am consistent in my testing, I spend very little time on taking care of my water. I'm aware of, and ahead of potential problems and have compensated before hand.

I believe in the methods espoused here because I have been using them for 6 years and they work flawlessly. I have had one MINOR algae bloom and that was cleared up in 24 hours--and due to my breaking my own rules. I have not had cloudy water, or any other major problems. But I did have problems before that, when I was using the pool store and "How to Tame the Pool Monster" for advice and hadn't found PoolSolutions.com or Poolforum.com/pf2.

[haze_1956]

PolyQuat should NOT be used when fighting algae.

You have said that on a quite a number of posts Carl !

But what exactly do you base that statement on ?

Ben even recommended using it against an existing bloom this year, although from what I gather it was as a last resort. However it did prove to be successful.
.

[chem geek]

Well, I just finished closing my pool today. I had my FC at 4, then added 48 oz of PolyQuat to my 19,200 gallon pool. FC dropped to 0. I then shocked it up, and, today, when I closed, FC was 13.5. I used Liquid Chlorine.

The 48 oz in 19,200 gallons is equivalent to 25 oz in 10,000 gallons so 2.5 times the example I calculated earlier. So I would expect this PolyQuat to consume 2.5 * 2.2 = 5.5 ppm of chlorine so it is not surprising that it consumed all of your 4 FC. In theory, it would have consumed another 1.5 ppm of the amount you added to shock, though you've said that you didn't notice this when you then added chlorine to shock level, though 1.5 might not be that noticeable when shocking to 13.5 (it's a 10% error).

[CarlD]

The 48 oz in 19,200 gallons is equivalent to 25 oz in 10,000 gallons so 2.5 times the example I calculated earlier. So I would expect this PolyQuat to consume 2.5 * 2.2 = 5.5 ppm of chlorine so it is not surprising that it consumed all of your 4 FC. In theory, it would have consumed another 1.5 ppm of the amount you added to shock, though you've said that you didn't notice this when you then added chlorine to shock level, though 1.5 might not be that noticeable when shocking to 13.5 (it's a 10% error).

That all adds up. I probably would have had FC of 15ppm.

The next question (and Buckman may answer it) is whether PolyQuat and Chlorine are working together or fighting. Is there a residual that PQ leaves that continues to be effective against algae growth? Or is it gone?

(BTW, if this gets more technical I'll move it to the China Shop.)

[chem geek]

(BTW, if this gets more technical I'll move it to the China Shop.)

Perhaps you didn't notice, but we are already in The China Shop! I started the thread here because I knew the issue was controversial and not for newbies, though I wasn't sure how technical it was going to get (of course, I tend to make things go that way... ).

And your point is quite valid of whether the chlorine breaks down PolyQuat, thus defeating the purpose of using it, or if it combines with PolyQuat to form a potent compound to inhibit and kill algae. Hopefully we'll find the answer to that soon.

Richard