Need answer to algae question - how much poly?

Posted below, but no one responded. If anyone can just respond briefly, I'd appreciate it.

Have 22,5k gallon IG, plaster, SWG. Have mustard bloom. Raised ch to 15 for a few days, it left briefly but came back. About the only other thing I can think of doing, besides elevating the chlorine back up for additional days, is to add poly.

The back of the bottle (60%) says 11 to 17 oz per 10k gallons. that would be about 28 oz to the whole quart full. But I was at another store today and saw that another brand of same stuff, same concentration, said 8 oz per 10k of pool? How much should I add?

Also, ch levels still elevated. Should I go ahead and add now, or wait for ch to come back to some level?

thanks

Something I don't see in your posts is what your cya level is. Can you supply that?

Pool store said CYA was 60 ppm. I don't totally trust them, so I am awaiting the kit I ordered from Ben and I'll post what that comes up with when I get it.

My autopilot says 60-80ppm is ideal.

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Originally Posted by SoCalBoo

Posted below, but no one responded. If anyone can just respond briefly, I'd appreciate it.

Have 22,5k gallon IG, plaster, SWG. Have mustard bloom. Raised ch to 15 for a few days, it left briefly but came back. About the only other thing I can think of doing, besides elevating the chlorine back up for additional days, is to add poly.

The back of the bottle (60%) says 11 to 17 oz per 10k gallons. that would be about 28 oz to the whole quart full. But I was at another store today and saw that another brand of same stuff, same concentration, said 8 oz per 10k of pool? How much should I add?

Also, ch levels still elevated. Should I go ahead and add now, or wait for ch to come back to some level?

thanks

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Boo, I recommend you read this article by Ben on algecides before proceeding with polyquat: http://www.poolsolutions.com/tips/tip08.html. If your CYA is really 60 ppm, chlorine is probably your best bet for knocking out the algae. If it's higher, you may have to use the polyquat or some other algaecide. Before using one of the bromine or ammonia based products however, you should read this article: http://www.poolsolutions.com/tips/tip10.html.

To answer your original question, if you do go with the polyquat, I'd dose at the rate that the manufacturer of the particular product you buy recommends.

The starting dose is usually twice that of the maintenance dose. However, for my 20K/gal pool I use 20oz to start and haven't been dissapointed yet! In fact, i've never had to go on a maintenance dose.

Michael

KurtV - I raised ch to at or above 15ppm for a number days and the mustard returned. No doubt the quickly rising pool temp isn't helping.

I guess I can just keep the ch level high for longer, but I doubt if 7 days (random example) will take of the problem if 4 days didn't. Eventually, you've to take care of the problem, so I am resigned to taking the next step - poly quat.

mwsmith2 - interesting you say that about the relationship between the intro dose and maintenace dose. the bottle says 11-17 oz per 10k gallons for intro, but only 2-4 oz per 10k gallons for maintenance.

I figured I'd just go with 25 oz (close to minimum range) and see how it goes.

So, does it matter what your ch levels are when you add poly? My ch level is still pretty from the supercholorination. In fact, despite having algae, my FC has been in the 6-9 range for about a week, and I haven't registered any measurable CC. I would think that with FC that high, it would attack the algae or some other 'goo' and make CC. Especially since I've been brushing the walls, steps and transitions every day for about 2 weeks. Hmmmm....

Quote:

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Originally Posted by SoCalBoo

Posted below, but no one responded. If anyone can just respond briefly, I'd appreciate it.

Have 22,5k gallon IG, plaster, SWG. Have mustard bloom. Raised ch to 15 for a few days, it left briefly but came back.

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You stated in a later post that your CYA tested at 60 ppm. If that is the case it is entirely possible that you did not get your FC levels up high enough. Ben's best guess CYA chart recommends 20 ppm
http://www.poolforum.com/pf2/showthread.php?t=365

I would give it one more try with chlorine and this time make sure you are at or above 20 ppm!

That was my thinking, too. That is why I asked him what his cya level was.

Once I get ben's kit, I'll have a better read on the CYA. The good news is that the mustard is much, much less than it was, so the superchlorination with bleach obviously worked, albeit not completely.

By the way, seems like the autopilot is calling for a rather high CYA level at 60-80...anyone have experience with using a lesser level with the autopilot? Or maybe that level is just fine and my experience is with lesser levels....

Thanks for the help.