Struggles maintaining FC

[wjmano]

I'm very new to this and could use some advice. I continue to lose FC, even though my CYA level is at 80. Here are my TF-Pro test results from yesterday:

FC - 1.5 (FAS-DPD)
CC - 2.0
pH - 7.5
TA - 90
CH - 325
CYA - 80
Salt - 3600 (my SWG reported 3500)
Water Temp: 83

After these results, I added 56 oz of 10% bleach to increase my FC to about 6 (10K gal pool). In addition, I have my recently acid-cleaned SWG cell running at 60% for 12 hours a day.

Now, this morning, my FC is back down to around 1.5 (OTO method) and my SWG is reporting an increase in salt of 3700 (it was reporting 3500 yesterday). We did have some swimmers in the pool yesterday, but nothing too heavy. The water is clear, but not especially sparkling clear.

Is my increased salt level part of my problem? And what can cause this? We haven't had any decent amount of rain for 7 weeks. If I can get some rain, I'm hoping this will help with the salt, rather than drain a portion of the pool.

Any help is appreciated!

Thanks
Bill

 

[AK-]

I'm not expert, CC is a by product of chlorine oxidation and CC of 2 is clearly the reason why you are losing FC. I'd start a SLAM Process.

 

[Mdragger88]

Check to be sure If your cell is functioning/producing fc - ie. when running u see bubbles or can pick up a sample coming out of the return that measures higher than the pool water.
If all is good then something is eating your chlorine & u need to do an Overnight Chlorine Loss Test to confirm.
Have u used any non chlorine shock (mps)? That can effect the cc reading for a bit.

 

[wjmano]

Sorry, I just realized I labeled my TC test result as “CC”. What I should have said was my TC was 2.0 and my CC was 0.5.

Since I have had this problem for quite a few days, losing significant FC daily, the overnight test sounds like a good idea to try.

 

[proavia]

In that case, change your PoolMath logs to reflect that. It will lead to less confusion when others are reviewing your logs.

 

[Jimrahbe]

W,

It is always a good idea to run an OCLT just to make sure whenever you have trouble maintaining your FC..

I suspect your cell is not working..

A T-15 in your pool, running 60% output for 12 hours should increase your FC by a little over 5 ppm per day.

Even in Florida, I would think that would be more than enough FC this time of year.

I'd run an OCLT with the cell off and see if you pass or fail.. Obviously, if you fail the OCLT, you have to do a SLAM..

If you pass, then I would run another OCLT with the cell on and the pump running all night. In theory, if the cell is working, you should see an increase in your FC of about 5 ppm.

Thanks,

Jim R.

 

[wjmano]

Wow, I’m thrilled I found this website — thanks for all the help!

1) I corrected my most recent CC log to reflect 0.5
2) Over the past month, to get FC levels up, I used dichlor treatments twice and 1 cal-hypo treatment...before I discovered this site - and nothing the past 10 days, except for liquid bleach & muriatic acid.
3) I have suspected issues with my salt cell (only 6 mos old). My pool construction co claims it’s working, with bubbles coming out of returns and by placing a test strip in front of the return...but I’m not entirely convinced.
4) I will run OCLTs as suggested by Jim to help isolate my problem.

With regard to my salt cell, how does my relatively high salt levels impact its performance? My system is currently reporting 3600 and won’t adding more liquid chorine and a SLAM (if needed) increase my salt even more? Hayward says 2700 - 3400 is ok, with 3200 being ideal for the cell.

Thanks again for all the help!
Bill

 

[wjmano]

I failed my OCLT last night. FC went from 4.5 to 2 in 9 overnight hours. I'll start my SLAM today after stocking up on some liquid chlorine.

My CYA is in the range of 70 - 80. I'm not too confident in my ability to determine when that black dot disappears. Given this range and my fairly high salt level, I plan to drain and replace about 25% of my pool first. According to PoolMath, this should take my CYA from 80 to 60.

Does all this sound appropriate?

Also, since it's difficult to judge how long this will take, do most people do an OCLT nightly, or do I wait until my twice a FC testing during the SLAM starts to stabilize?

Thanks again to all the great help. I'm hopeful, once I know what I'm doing I can return the favor some day.

 

[CrystalRiver]

It's always easier to SLAM at lower CYA. And you're right that adding liquid chlorine adds some salt to the pool.

There are three end-of-SLAM criteria. No point in doing OCLT until the other two are met. What does your water look like? Any patches of algae, or "dust" on the floor? Any cloudiness, or could you call heads or tails on a coin in the deep end?

 

[Mdragger88]

twice a FC testing during the SLAM

Its best to test & replenish fc every couple/few hours at the start of the SLAM Process
Towards the end you will see the fc level start to hold more & be able to just do 2 or 3 times a day. Just remember that every hour fc is below slam level for your cya algea is gaining a foothold.

 

[wjmano]

4 PM and still waiting for my pool to refilled before starting the SLAM process. Will probably take a few more hours. Tempted to pour some chlorine in there right now, but figure it's best to have the pump running when doing this. Plus I want to test my pH before adding any large quantity of chlorine.

Once SLAM has started, checking FC every few hours at the very beginnng was suggested. Does this mean it's best to start in the morning, rather than late at night?

My water hasn't been crystal clear for quite some time. Love the idea of being able to call heads or tails on a coin in the deep end to judge water clarity...I only have 5 ft of water. Wonder if I can get by with a smaller coin, rather than a quarter. Hopefully I'll know this when the SLAM is over.

 

[Newdude]

I only have 5 ft of water. Wonder if I can get by with a smaller coin, rather than a quarter. Hopefully I'll know this when the SLAM is over.

Yup. Easily. Nickels are hard mode and dimes are expert level water. You’ll get there

Some of us like to use the screws on the main drains to see if they are flathead or Phillips.

 

[Mdragger88]

Does this mean it's best to start in the morning, rather than late at night?

I guess that depends on what your sleep/work schedule is . There have been people who stayed up all night to complete a slam as quickly as possible (I don’t really recommend that).
Many people who work during the week start on the weekend so they can tend to it more frequently. I personally feel that there’s no time like the present when it comes to the war on algae. For instance if you began right now depending on your bedtime you could get several cycles in & then begin again early in the morning.

 

[CrystalRiver]

I agree that whenever you are ready is the best time to start. Even if it's only one or two cycles before bed. Every minute you keep it in swamp mode, without adequate chlorination, the algae are multiplying.

 

[Newdude]

There are 100 ways to skin this cat. I vote for the don’t let it get any worse until the weekend (or whenevs your schedule is SLaM friendly) and hit it HARD with guns a blazing and full effort.

You lose a lot of ground anytime you step away from it, and it took effort and a decent amount of chlorine to get that progress.

But any progress that you kept when it’s time for real, is less of a battle at that time. So there is that too. It all come down to how you see it.