Tired of bad advice from pool company

[aylad]

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

[PoolDoc]

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

[keith]

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

[Watermom]

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.

[keith]

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

[PoolDoc]

Did you get a K2005 or a K2006? There's a BIG difference!

Anyhow, get some acid and bring the pH down. Don't worry about acid demand; just add a small dose and repeat till you get there.

If you are going to use bleach or cal hypo, add CYA -- 1# will add about 4 ppm if fully dissolved.

If you are going to use dichlor or trichlor, add less CYA, probably only 5#.

Dunno why you have CC -- unless you've got a K2005. DPD tabs are a pain.


Ben

[CarlD]

Two good things about a gunite pool:
1) It can stand very acid water without melting the liner (vinyl is in danger once you go below 6.9)
2) It can stand VERY high chlorine levels, like 50ppm or more (where vinyl will bleach). This is good for clobbering algae but you still can't swim till it comes down to levels Ben recommends.

Now that your pH is high and your stabilizer (CYA) is zero, Trichlor tabs and/or dichlor powder is a good option. Both will lower pH and raise CYA levels.

But with Gunite, your cal is below the recommended 200-400ppm. Cal-hypo is a good chlorinating option for that as it adds calcium.

Personally, though, even with gunite, I'd worry about calcium levels last.

BTW, when your pH is at 7.6 or lower, your T/A will measure lower too, but it should be fine.