Back with my first TF-100 results. Huh?

[thewritegirl]

As I said in a previous post, I am a complete pool-care newbie, so be gentle with me. I got my test kit today (super fast shipping and arrival, btw) and have ran my first set of tests.

They are...
FC 3.5
CC 0 (I'm not sure if I get the difference here between the Free Chlorine and the Combined Chloromines)
TC 3.5 (Right, 3.5 + 0?)
pH is super, duper terribly low. I'm thinking less than 6.8 by color?
T/A the test stayed pink - does that mean 0?I added the R-0007 and mixed, then added the 5 drops of R-0008 and mixed. Test said it would turn green, but it stayed pink. Twice.
CYA is about 70, I think. That's a bit subjective.
I didn't bother to test the CH, as we've got a vinyl liner and our water is clear.

So, to sum it up, I need to find out if the T/A result means 0, which would tell me if I want to add borax or baking soda to raise the pH, right? Also, the CYA is on the high side (we've had the pucks in there, so I'm sure that's why. I took them out today). Is that still acceptable?

Like I said, the water is clear, but I've still got a bit of green algae in the corners where I couldn't reach with my scrubber. Do I need to shock to get rid of that, or would it be sufficient to just srub it (I think I found a better scrubber that will reach)?

Thanks, everyone!
Mary

 

[prov431]

Hello Mary,
I'm fairly new at this myself, but have been through much of the same things you describe.
I can tell you this much:
Use the pool calculator found at www.poolcalculator.com It's the best thing available to aid you in putting in the right amount of chemicals. Make sure you fill in the blank at the top left for pool size (gallons) before using it each time.
Secondly, your FC level needs to be adjusted to suit the amount of CYA in your pool. Again, use another great tool found here: http://www.troublefreepool.com/viewtopic.php?t=2346
This chart will tell you that you need to hold a FC target of 8 ppm based on your 70 ppm CYA. Anything below that and you will run the risk of algae.
Third, the definition of CC is: "Combined chlorine is an intermediate breakdown product that is created in the process of sanitizing the pool. CC causes the "chlorine" smell some people associate with chlorine pools. If CC is above 0.5 you should shock your pool. CC indicates that there is something in the water that the FC is in the process of breaking down. CC will normally stay at or near zero as long as you maintain an appropriate FC level and the pool gets some direct sunlight."
(That is directly from the pool calculator hyperlink on CC)
Forth, I had the same issue with my TA when I first started. You are correct in thinking that you are very low.
You will need to fix the PH and TA, which is somewhat of a balancing act until they both come into range. Once you get your TA up around 90 or so, your PH will hold itself more steady. Here is another definition of TA from the pool calculator page:
"You can raise TA with baking soda. It is often best to make large TA adjustments in a couple of steps, testing the water after each one, as adding baking soda will also affect the PH and you don't want the PH going out of range. You can lower TA by lowering the PH to between 7.0 and 7.2 with acid and then aerating the water to bring the PH back up. Aeration can be supplied by spa jets, waterfall, fountain, rain, kids splashing, compressed air, or by aiming a return up towards the surface so it breaks the surface of the water and causes bubbles. This process is then repeated until you reach the desired TA."

Good luck!

 

[JasonLion]

I estimate about 11,000 gallons in the pool.

That test result means TA is zero, or very close to zero.

You need to get your PH and TA up to reasonable numbers as quickly as possible. In particular you need to get PH to at least 7.0 and TA to at least 30. You can do this with either soda ash/PH Increaser or a combination of baking soda and borax. If you have a base demand test you can use that to estimate chemical amounts. Otherwise, because you don't know how low the PH really is, the test will report numbers lower than 6.8 as 6.8, you need to add chemicals in batches, give it half an hour to an hour to mix in and retest to see how you are doing.

With CYA around 70 you want to maintain your FC level between 5 and 10 and never below 5. To kill the algae you will need to shock the pool, which means raising FC up to 20 and holding it there by frequent testing and addition of chlorine, until the FC level remains the same overnight. CYA around 70 can be a little annoying, note the fairly high FC levels required, but it is manageable.

Do you have a CH number? It is a good idea to check that the CH level isn't too high.

 

[thewritegirl]

Thanks you guys - my biggest question was about my T/A level. So now that I know that means I'm really low, I need to use mainly baking soda to get that up, because my pH is low, too. I used the pool calc, and it said that I'm going to need about 16 lbs of baking soda to get my T/A to 100. Would that put my pH too high - as in, should I put in a certain amount of baking soda and then switch to borax?

And, it sounds like I do need to shock, and then maintain the pool with a slightly higher than normal chlorine level because of my higher CYA. Right? I just want to confirm before I go pouring crazy amounts of anything into the water! I'll get this figured out yet...

Mary

 

[MikeInTN]

I'd go ahead and add 8 - 10 lbs of baking soda now, wait an hour or two, and then measure your pH and TA again. You really want to get your pH up in target range pretty quickly, especially with it being so low. I don't know how much baking soda will increase your pH, but you need to get your pH up as soon as you can, so after 10lb if your pH isn't anywhere near 7.2, I'd think about getting some borax to bring it up. You can adjust your TA with the rest of the baking soda and, if needed, lower your pH with acid if it goes high. Main thing is, get your pH up in range as soon as you can.

The rest of what you asked is dead on. Yep, you'll need to maintain higher FC due to your CYA being 70, and you'll need to shock to get rid of the algae in your pool now.

 

[giulietta1]

Thanks you guys - my biggest question was about my T/A level. So now that I know that means I'm really low, I need to use mainly baking soda to get that up, because my pH is low, too. I used the pool calc, and it said that I'm going to need about 16 lbs of baking soda to get my T/A to 100. Would that put my pH too high - as in, should I put in a certain amount of baking soda and then switch to borax?

I'd suggest soda ash (washing soda/sodium carbonate) which raises both TA and pH at once. I had the exact same TA/pH issue when I first tested my pool. The TA test immediately went pink, never turned green!

Baking soda has little impact on pH, mostly raises TA. Borax has little impact on TA, mostly raises pH. Soda ash (washing soda) raises both and would be ideal for your purposes. Usually one wants to eliminate algae before adjusting other water factors, but in your situation it would probably be better to get the pH and TA close to normal parameters first!

And, it sounds like I do need to shock, and then maintain the pool with a slightly higher than normal chlorine level because of my higher CYA. Right? I just want to confirm before I go pouring crazy amounts of anything into the water! I'll get this figured out yet...

Yes, do shock, and make sure you also brush the pool, ESPECIALLY those places where you can actually see algae! At your CYA level, shock is FC of 27.5. Normal FC for your CYA is 8, range of 5-10 ok.

 

[JasonLion]

Soda ash has some advantages, baking soda and borax will work also. Just do it soon, ie don't wait till you go to the store if you don't have to.

Any chemical you use, take it in steps. Don't add the full calculated amount all at once. Let it circulate for an hour and test again and adjust from there. And if you are using baking soda and borax, start with baking soda before the borax.