Low Chlorine Problems

[nscclukas]

Not sure if this should be under chlorine or algae?

I'm still fighting to get my chlorine levels to stay high. It's a real battle, been checking 3 times a day & making slow progress. I have put in 20 gallons of 6% bleach, after filling the trash can with empty bottles, I decided to go to Menards & get the 15% LC, & have put in 10 gallons of that, thus far.

This morning readings:
Fcl:3.57
Tcl:6.8
PH:7.1

Any ideas on how to kill this algae? I have scrubbed last two evenings Should I vacuum? Can't see the bottom of the pool, 3 feet at best. I have had it on filter continuously. How about backwashing? I have a couple times for a couple minutes, do I need to backwash till foamy bubbles are done? Pressure hasn't been high on gauge. Just wondering if I'm doing things right?

[PoolDoc]

If you want to know how much more chlorine it will take, you can get an estimate by doing a chlorine demand test:

Bucket-testing-for-chlorine-demand

But do NOT back off while you are checking: with algae, either YOU are winning, or THE ALGAE is winning. There is no 'coasting'; when you coast for a day or two, the algae will recover, and you are likely to lose 100% of any ground you've gained!

By the way, you NEED TO GET A TESTKIT. Your FC=3.57 ppm result tells me you are using a somewhat bogus digital reader, which in turn tells me, that you don't know -- reliably -- what's in your pool

[CORRECTION from ORIGINAL VERSION: The Lamotte Color Q is considerably better than the digital strip readers, which also produce 2 decimal point results. But the evidence still is that the unit's fundamental accuracy comes nowhere close to 2 decimal points, and does not approach the accuracy of titration methods, like the Taylor K200x series. In addition, there's an intrinsic problem with colorimetric methods for calcium and alkalinity: such methods are inherently logarithmic in progression, rather than linear like titration. Thus, color methods become more and more imprecise as the value increases. So the Color Q may be MORE precise than the K2006 for FC=0.1, but MUCH less precise for FC=10 or CH = 400. Unfortunately, this decreasing precision is masked the digital conversion process, which pump out multi-decimal results, even when the unit can barely distinguish 400 ppm CH from 500 ppm CH!]

Please go get a cheap OTO kit, if nothing else . . . and then dose with bleach till you reach DARK yellow, or orange-tinted yellow.

Ben

==============================


+ Get a cheap OTO (yellow drops) / phenol test kit, or if available at YOUR Walmart (check availability), get the HTH 6-way DROPS test kit, which is compatible with the Taylor K2006. Test the pool as soon and you can, and post the results. If you get the 6-way kit, ALSO test the water you FILL the pool with, especially if it's a well, and post THOSE results as well. (The HTH is the best available kit you're likely to find locally, but it's not the K-2006. It can only provide rough measurements chlorine levels above 5 ppm, and it measures "TOTAL" hardness, rather than "CALCIUM" hardness, which is not ideal.)

+ Having a good test kit makes pool care easier for EVERYONE. A good test kit means a kit that can test chlorine from 0 - 25 ppm, pH, alkalinity, calcium hardness, and stabilizer with reasonable accuracy. Test strips (AKA 'guess-strips' ) do NOT meet this standard. Some pool store testing is accurate; most is not. The ONLY way you'll know whether your pool store is accurate or bogus, is by testing accurately your own self. On the other hand, pool store 'computer' dosing recommendations are NEVER trustworthy -- ignore them. They are designed to sell more chemicals than you need, and WILL cause many pool problems.

+ We recommend the Taylor K-2006 test kit, which meets the requirements above, for many reasons. The HTH 6-way drops kit is a great starter kit, and is compatible with the K2006 (it's made by Taylor). There are a few alternatives; for example Lamotte makes an FAS-DPD kit that's OK -- but it costs 3x as much. But, we're not aware of any test that is better, and since we are all familiar with the K-2006 (and can help you with it) we recommend it exclusively ( Test kit info page )

One caution for the 2012 season: Amazon does not stock the kits directly. So when buying at Amazon, Amato is our current preferred seller. However, they often don't list enough stock to last the whole day, so try order mid-morning. You should expect a delivered cost under $60 for the K2006A and under $95 for the K2006C. If you can't find that, wait a day.

+ Here are links to the kits we recommend (you can check local availability on the HTH kit, using the Walmart link):

HTH 6-Way Test Kit @ Walmart
Taylor K2006A (3/4 oz bottles) @ Amazon
Taylor K2006C (2 oz bottles) @ Amazon

[Watermom]

Ben,
Although I know nothing about them -- maybe you do --- this member has a Lamotte Color Q 7 digital test kit.

nscclukas,
The pH of 6.8 is too low. You should use some 20 Mule Team Borax (laundry aisle at Walmart) to bump it up to between 7.2-7.8.

[PoolDoc]

Noted and corrected. Thanks WM.

(The Color Q *is* substantially better than strip readers, but still is a colorimetric method, and thus much less accurate than the 3 or 4 decimal point results imply.)

[nscclukas]

Tell me if this sounds right? I added the 4 gallons of 15% LC, scrubbed & vacuumed, thought I'd check the Cl before calling it a night, say 2 hours later.
Fcl:4 Tcl:5.6 Can the algae be eating up that much Cl? Or do I have old weak bleach & that's why I can't get ahead?

[Watermom]

Can the algae be eating up that much Cl?

In a word, yes. Keep hammering it with bleach. We really aren't going to be advise you too well without a CYA reading. That is a critical value to know when you are trying to clean up an algae bloom.

[nscclukas]

Yes weak Cl? Or, Yes the algae can consume that much Cl?

My first couple posts I explained my CYA is high 125+ my tester only goes that high. I could dilute &multiply multiply if necessary, but I'm pretty sure it's below 200.

The local pool company said my CYA was168 about 6 weeks ago, but he said he couldn't give me accurate readings because I was keeping the Cl level too high at 8. He insisted that I shouldn't have the Cl over 3, said it wasn't safe for swimming & I a waste of $. I tried to explain to him that as CYA levels rise, the need for higher Cl levels, but he disagreed, said he's be doing pools for 30 years & knows better. I said, well of course, you make most your $ selling shock, algaecide, & other unnecessary stuff, not off of helping customers maintain a good clean healthy pools.

So, needless to say, he wasn't very happy with me.

[nscclukas]

I got my old test kit out to double check the #'s & they are right.
This evening:
Fcl:1.5
Tcl:2.92
PH:7.1
I added 3 gallons of the 15%LC this morning & it's all but gone apparently. I'm. going to add 4 gallons of the LC & a box of borax, scrub & keep after it I guess. I was just wondering if I needed to do anything more or different? Thanks

[Watermom]

We really need a CYA reading to be able to advise you. Does your kit test for CYA ?

[PoolDoc]

I added 3 gallons of the 15%LC this morning & it's all but gone apparently. I'm. going to add 4 gallons of the LC & a box of borax,

Just found out this morning that many SCP distribution locations buy boxed jugs of "liquid chlorine" by the truckload in the SPRING, and let them sit all summer. At this point in time, most of those jugs are probably 1/2 strength or less! In Nebraska, it's not likely you're getting fresh bleach from a pool store that gets weekly deliveries. What's more likely is that what you are buying is some small fraction of its original strength.