Ben - I bought a Taylor DPD-FAS kit. My CYA is above 100. Extrapolating it looks like 150-175. Probably closer to 175.
 
					
					
						Ben - I bought a Taylor DPD-FAS kit. My CYA is above 100. Extrapolating it looks like 150-175. Probably closer to 175.
Keith,
You can use the "how to test if . . ." link to get an explanation of how you can 'extend' your CYA test to cover the higher range.
Then, use the "Best Guess" page to find the right chlorine range . . . and you should be good to go.
Of course, you'll need to switch to either calcium hypochlorite or bleach (sodium hypochlorite) as your primary source of chlorine.
You can give away, or seal up, your stabilized chlorine. You might want to hang on to it long enough to see how fast your CYA drops (no need to test more than 2x per month). If it looks like it will take more than a year to get below 100ppm, you'd better give it away. Old chlorine tabs and powder tends to give off a variety of noxious fumes that aren't good for you and are TERRIBLE for wiring in your garage or storage shed.
Ben
 
					
					
						So help me understand what you're saying, - even with a 150+ CYA level, do I need to drain/refill? And you suggest to "see how fast your CYA drops". I thought the CYA never drops. So I remain in that confused state I started in. What is the resolution to the CYA levels? Leave it as it is and monitor FC levels and forget about it? Drain? Not drain?
The CYA is only going to drop by backwashing or by splashout, so it's possible for it to fall some during the swim season, but not likely by very much. Ben is by far the most knowledgeable one here, and I'm guessing he has a reason for not draining/refilling to get the CYA under better control, and would defer to him, but just wanted to add my opinion here that it certainly won't hurt to drain/refill some of your water, and personally, if it were my pool and could do so without much of a problem, I would go ahead, unless the levels of other chems in your fill water would substantially change the current levels in your pool.
Janet
Janet
Keith,
If you'll look at the Best Guess chart (link below), you'll see you can operate in the 8 - 15 ppm range, once your algae is gone. If you have a sand filter, you're going to losing about 1% of your stabilizer every time you backwash, plus whatever splashes out. (If you've got a DE or cartridge filter, it will be less.) But, for now, you can clean up, and operate just fine right where you are, now that you've got a FAS-DPD based kit.
You may find you like it. With stabilizer that high, you can chlorinate on Monday to 15 ppm or so, and not have to add again possibly for the entire week. Since the chemicals you need to use have to be hand fed unless you buy some sort of feeder system, this offers you some real benefits.
Or you may find you don't like it. If so, you can still drain and refill later.
But, until your algae is gone, I'd recommend adjusting your pH to around 7.8 (7.6 is ok) and then dosing to about 25 ppm. (Remember, you can't test pH once you go above 15 ppm chlorine.) Once there, brush every day or so, and dose up to keep it there till your algae is 100% gone. If you find that it's not disappearing, you can increase the chlorine somewhat, or you can look at using a phosphate remover -- but that's messy.
You *can* swim at 25 ppm, if your pool is warm enough. Just wear an older swimsuit, since those chlorine levels are not good for fashion suits. You may, or may not, find that those levels of chlorine dry your skin some.
Ben
Ben
Last edited by PoolDoc; 04-21-2011 at 07:11 PM.
PoolDoc / Ben
 
					
					
						Thank you guys for your replies to my problem. I did dose high with bleach, the pH was good, and the algae is still not reacting. And it has stained some areas of the gunite surface. I'm going to drain today, power wash (delicately) to remove the algae and refill. I don't have a problem monitoring and adding BBB when necessary but I do have a problem brawling with this extreme CYA. Here in North Texas the summer sun is brutal and I can't see starting out with algae growth!
If you would please direct me to one or more of your links or a good post on starting up a pool with fresh (tap) water using the BBB program.
Thanks very much,
Keith
Be careful. Totally draining a pool is often not a very good idea. Particularly if the water table is high. Your pool can literally pop out of the ground. A better option might be to do a couple of partial drains and refills. You can probably safely drain 1/2 to 2/3 of the water. Then, retest cya. If still too high, can do another partial drain and refill. I realize that you have a large pool and this may be a big expense waterwise. However, if you do get the cya to a more manageable level with some partial drain/refills, then we can help you get rid of the algae. Won't be necessary to do a powerwash.
If you do drain and refill, repost with a set of water testing results taken from your fill water. It will be easy to help you get it balanced. Have you done any reading on our sister site www.poolsolutions.com ?? Lots of good info there. Repost with numbers and we'll make recommendations for you to get started off on the right foot.
 
					
					
						Hi - in response to your last post, I've drained and refilled. Here are my numbers after refilling based on my K-2005 Taylor test kit. To recap it's a 28K gunite in-ground pool
Free Chlorine - 1.0
Combined Chlorine - 2.0
pH - 8 (acid demand was 2 drops)
Total Alkalinity - 120
Calcium Hardness - 160
CYA - 0
Again my goal is to use the BBB method to balance the water. Your help is most appreciated!
Keith
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