What am I doing wrong!

[md22]

Hi all,

New to BBB and working to get my pool in order. I've finally gotten the pool in balance, but am having problems maintaining FC.

Here are the numbers:

TC: 3
FC: 3
pH: 7.2
Alkalinity: 100
CYA: 40


All of that looks fine to me, but my FC drops to 0 overnight and my TC falls to 1. This morning I had to add a 3 gallon Ultra bleach (6%) to get the numbers back up. I had been adding bleach, but did not have CYA up to maintain it. Now that CYA is level, should I have that much of a drop?

Do I still have something growing and need to shock the pool completely? If so, what should my TC and FC reading get to for shock?

22k inground vinyl pool.

Thanks!

 

[Bama Rambler]

Are you using the Pool Calculator (PC) to figure the amount of chems to put in? You should also read Pool School to learn how to shock and do an overnight FC drop test if you haven't already.

pH is a little low and needs to be brought up with some [s:2dmutpu9]baking soda (sodium bicarbonate)[/s:2dmutpu9] Borax (20 Mule Team) . PC will tell you how much to add. [edit] Sorry about that. That's what I get for doing too many things at once. [end edit]

It looks like you're using an OTO chlorine test kit or strips to test with. You really need a good kit if you don't have one. Look in my sig to see my favorite.

Now to the real problem. You are apparently losing FC overnight. Is that correct? Are your checking the FC after the sun is off the pool and again the next morning before the sun hits the pool?

If so, then you have organics consuming the FC and you need to shock. With a CYA level of 40 you need to shock to 16 ppm. The PC can tell you how much chlorine to add to get there but if you're not using a FAS-DPD chlorine test kit you won't be able to measure it, and you have to, in order to shock correctly.

 

[md22]

Sorry, the FC drop was overnight. I was using a calc that I had downloaded (I thought from here), but your online calc is WAY easier.

I've added 20 Mule Borax to get the PH up and I'm off to get a better test kit (yes, strips was correct) and 593oz of 6%!

I'll post my results in the morning, thanks for the reply.

 

[frustratedpoolmom]

You are better off ordering one of the recommended test kits online - often the pool stores don't have the correct kit and will try to sell you an inferior one.

Borax is the correct product to raise the PH - but I wouldn't bother raising it anymore until the shocking process is complete. Just focus on that for now. 7.2 isn't so low that it needs immediate action...

It definitely sounds like you aren't done shocking.

 

[md22]

Numbers this morning:

TC: Somewhere between 5-10 on the test strip
FC: Somewhere between 5-10 on the test strip
PH: 7.2
AL: 100
CYA: 40

So FC did not drop significantly overnight, but TC dropped from over 10. Did I get over the hump?

Ordering a real test kit today.

Thanks!

 

[frustratedpoolmom]

Did I get over the hump?

Won't know until you get the good kit.