Polyquat or not ?

[haze_1956]

Result of experiment of whether to add Polyquat at closing.

Closed with Poly in fall 2005 and opened in Spring 2006 to clear water and clear bottom with CYA reading of 30. Believe it was 30-40 at close.

Closed in Fall 2006 without Poly. Opened in Spring 2007 with clear water, but a film of dead algae on the the bottom and a CYA reading of Zero.

Just wanted to post info for comparison by others. Maybe we can gather enough info to see if there is a correlation.

[CarlD]

I always close with poly. No algae on the floor but LOTS of black/brown soot/dirt/pollen. And clear water. Just comes with living in NJ. Even cloths in closets get covered in dust fairly rapidly. The Blue Dolphin gets it with 2 or 3 cycles.

[NWMNMom]

I have never closed without. I'm too scared at what I would find.....

[ChuckD]

This may be a testament to how a Cl shock will kill your Poly: I closed last fall with a double dose (half gal. in 20K of water) and then a shock, and while I can see the bottom in the four foot end, the deep end is dense green. I also use only a mesh leaf net as a cover.

[chem geek]

Note this post (http://www.poolforum.com/pf2/showthread.php?p=40356&postcount=25) where a chemist at Buckman Laboratories gives the recommended closing procedure which shocks with chlorine first, then lets the chlorine level drop before adding PolyQuat.

Richard

[CarlD]

OK, here's how I do it and EVERY season I open to clear water. I take into account that the PolyQuat in large amounts causes the FC level to collapse. But I don't do this until the water is AT MOST in the low 60's, colder is better.

1) shock the pool

2) Add 1 quart of polyquat.

3) Wait 24 hours for the chlorine to drop.

4) Shock it up again.

5) Close

Yes, it's really all it takes.

[haze_1956]

I found it interesting that the CYA was at 0

Wondering if the algae ate it last fall and then froze and dropped to the bottom.

[CarlD]

My CYA dropped from about 40 to 25 over the winter...but I had lot of dilution from rain and snowmelt

[chem geek]

Many people find their CYA level dropping to 0 over the winter. Though it is possible that algae eat it for food, what IS known is that there are anaerobic bacteria that normally live in soil that definitely consume CYA. It is very possible that at least for pools where the FC gets to 0 that these bacteria consume the CYA. If they do, then they produce ammonia as a by-product which would mean needing LOTS of chlorine to open a pool.

Some users report the CYA dropping over the winter even maintaining chlorine levels. This happened to me this winter going from 20 to 10 (approximately) and I had no dilution (I have an automated opaque pool cover), but in past winter's I hadn't seen this and I've maintained chlorine levels every winter.

Richard

[haze_1956]

Alk is down too. 120 to 70.

Lot of start up this year !! LOL

Hate it when an experiment turns around and bites me in the wallet.

:(

I'll use poly this coming Fall and see what I find in Spring 2008.

[ChuckD]

Note this post (http://www.poolforum.com/pf2/showthread.php?p=40356&postcount=25) where a chemist at Buckman Laboratories gives the recommended closing procedure which shocks with chlorine first, then lets the chlorine level drop before adding PolyQuat.

Richard

Right, Richard, very familiar with that post and knew about the nullifying effects at higher concentrations. Thanks for the info. My pool's not at my primary residence tho, so I didn't have time to wait for Cl levels to drop. Just the weekend.

But I have a follow-up to that referring to your comment about the 'heavy molecular weight' of the Polyquat and another, as yet unresolved controversy concerning it. Some here say that a DE filteration system will filter out the Polyquat, I remain unconvinced. Do you think, given its higher weight this is a concern? I don't have a bypass, or circulate-only mode on my Hayward EC-65, so it's a real concern for me.

[chem geek]

I've sent an E-mail to my contact at Buckman Laboratories that makes PolyQuat. I'll let you know what they say but I suspect that the PolyQuat polymer, though long-chain and viscous, is not 5 microns in size and that's about the smallest that a DE filter can capture (I believe -- 10 microns is what usually is quoted for "typical"). I'll let you know what I find out.

Richard

[chem geek]

Here's the response I got from Dr. McNeel (with some definition comments of mine in brackets):

The molecular weight of PolyQuat is in the low thousands (~3000-5000 daltons [each polymer unit has a molecular weight of 253.17 as seen in this post (http://www.poolforum.com/pf2/showthread.php?p=39948&postcount=15) so the polymer has roughly 12-20 units and each unit is very roughly 0.01 microns in length], so an UNCHARGED filter is not going to remove it from solution, no matter how small its effective pore size may be. However, an anionic [negatively charged] surface (such as an cation exchange resin) will definitely remove PolyQuat from the water. In fact, PolyQuat will bind so tightly to a polystyrene-based strong-cation exchange resin that even concentrated hydrochloric acid will not displace it from the resin.

Diatomaceous earth and other silica-based structures will have a net cationic [positive] charge on the surface at neutral or acidic pH levels and hence will not tend to bind PolyQuat too much; however, if the pH is sufficiently high, the surface can become anionic [negative]. I don't think that the pH levels normally found in pools will be sufficiently high to be a problem for PolyQuat. Studies have been carried out in the past with sand filters (another silica-based filter medium), and PolyQuat loss on the filter medium was not found to be a problem.

It is interesting to note that if one were to use a water softener (cationic exchange resin) to try and reduce Calcium Hardness, one had better not have any residual PolyQuat in their water or else their water softener will essentially be ruined.

Richard

[ChuckD]

Good to know, thanks.
When I close this fall (shudder) I'll try to allocate more time to do it right.

[chrisexv6]

I have to ask (sorry to resurrect an old thread)....

I have a mesh safety cover on my vinyl IG pool. Closing it consists of shocking to high FC (15-20), adding PQ and letting it circ for 24 hours, then covering the pool.

Every year, I open and the water is clear but the bottom of the pool is a mess with algae. Granted it doesnt take long to get rid of it (a couple vacuum to waste sessions and its gone), but I was wondering if there is a way to avoid it.

The only thing I can think of is that the mesh is allowing too much sun thru. I wanted to open it earlier than normal this year but current projects forced me to open on Memorial Day weekend. Is my best solution just to open earlier next time?

Thanks!
-Chris

[ChuckD]

I'll wager that it's not algae, but some other kind sediment you're seeing.
I think if it was algae the water wouldn't be clear. The algae would still be alive and not dead on the bottom.

If you use a mesh cover (as I do too) expect all manner of stuff to blow in, like tree pollen, etc.
But how does your water stay clear when you use basically the same technique as I do, and mine is (was) pea soup.


Chuck

[chrisexv6]

Thats a very good question :) And I couldnt believe it with my own eyes, but it was definitely clear (you could even see the main drain in the deep end). Maybe we had so much extra rain water that it caused enough dilution to remain clear? Dunno. We did have an awful lot of rain in April.

I suppose what was on the bottom could have been some sediment, but it was coming out green and slimy whatever it was, and there was a lot of it. I just assumed algae because it looked like a dark green. Shocked the pool for about 2 days, vacuumed to waste and 90% of it went away, I brushed the rest towards the main drain (aka "lazy mans vacuum") and am waiting for the water to completely clear up again (just a little cloudy towards the deep end, clear in the rest of the pool). All in all took 4 days from open to swimmable. Id like to see it down to 2, because Im lazy that way :)

[Rbrenton]

Hello all, sorry to open up an older thread, but I too open up a NJ pool to pea soup every year using a mesh cover. A friend insists that their pool is crystal clear in the spring because they use a solid tarp under the mesh which is designed to use the mesh cover's anchors.

I can't see how this would impact green algea, but I don't know what chemicals are used by their closing company. Mine apparently doesn't do much, but I'm never around when they show up in early October.

Does anyone have an opinion on what this solid layer is capable of?

[doggie]

Hello all, sorry to open up an older thread, but I too open up a NJ pool to pea soup every year using a mesh cover. A friend insists that their pool is crystal clear in the spring because they use a solid tarp under the mesh which is designed to use the mesh cover's anchors.

I can't see how this would impact green algea, but I don't know what chemicals are used by their closing company. Mine apparently doesn't do much, but I'm never around when they show up in early October.

Does anyone have an opinion on what this solid layer is capable of?

We also have a mesh cover and opened to a crystal clear pool. The 2 things we did were 1st: we opened in early May before the water had a chance to heat up too much (we are in West Michigan). And 2nd: we used a Keeper Klean on the water which prevented sunlight from getting in. http://www.poolproducts.com/-c-FCATHPIKKC-FNM-92.htm

I'm not sure which one did the most good, or maybe a combo of both, but from now on we'll always use this method.

[myLABSpool]

Has anyone been told to use an enzyme called "pool magic" at closing to prevent algae growth? My neighbor uses it and he said a few pool stores recommend it in addition to algaecide.

I was only planning on shocking with liquid followed by polyquat before I blew out the lines and covered. Any thoughts or experience on using or not using pool magic at closing? Or if I'm using Polyquat is that enough?

FYI I'm using a mesh cover on a 24K gal vinyl pool in ROC NY.

Thanks
Andy

[chem geek]

According to this link (http://www.intheswim.com/Pool-Chemicals/Natural-Chemistry-Enzyme-Pool-Chemicals/Pool-Magic/), this enzyme product will break down organics to help prevent scum lines, but it says nothing about killing algae. Technically, enzymes are catalysts and simply accelerate specific chemical reactions, in this case the breakdown of organics by chlorine (or, to a lesser extent, dissolved oxygen if there is no chlorine left). Though technically algae is organic, I don't think this product will do much good at killing algae faster than it can reproduce, but it might speed up the breakdown and clearing of already killed algae IF chlorine is present.

So chlorine is really the key to having the enzyme work effectively -- it can be thought of as a "chlorine helper".

The bottom line is that I don't think this is particularly helpful for winter closing unless you have a modest amount of organics (i.e. leaves, etc.) fall into your pool and have both chlorine and this enzyme to break them down more quickly. The PolyQuat is a better choice for preventing algae, though simply regularly adding chlorine will work as well -- probably only once a month or even less since at cold water temps the chlorine lasts a LONG time.

Richard

[myLABSpool]

Chem Geek,
Thanks for your reply. Based on your assessment, I'm going to go with straight Polyquat 60 and chlorine. In the spring we'll see whether my two neighbors (that used Pool Magic) have clearer water or not.

Thanks
Andy