First TF-100 Tests - Results and Questions on Plan - Update: Resolution and pics!

[SQLGeek]

I got my kit today and ran a full battery of tests for my new plaster pool.

Here's the log:

PoolMath Logs

I'm currently running trichlor pucks and have been since startup a few weeks ago. Three pucks to be exact and they have not been dissolving very fast on a setting of 5 on the Pentair Chlorinator. I am shutting it off and pulling them today and switching to just 10% liquid chlorine.

Water Temp 90* F
OTO CL - 0.5
pH - 7.8 - 8.0 ? I logged 8
FC - 0.5
CC - 0
TA - 90
CYA - 20? 30? Dot never completely disappeared and I ran out of water between 20 and 30. I recorded 30 to round up but 20 may have been more accurate.
CH - 350

Obviously FC is low. Based on the CYA Chlorine chart I am going to target FC of 6. Per Pool Math I need to add 3 quarts, 2 cups. I will be doing that now.

pH has crept up from last week but has been keeping around this level. Pool math tells me to add 1 qt, 1 cup to lower pH to 7.2.

I have a spillover and kids splashing so I should have plenty of aeration to raise pH back up.

I also need to add CYA.

TL;DR

Plan

• Remove trichlor pucks from Chlorinator
• Add 3 qt, 2 cup of chlorine to pool now
• This evening add 1 qt, 1 cup of Muratic Acid
• Test FC, pH, TA tomorrow
• Find CYA tomorrow

Questions

• Does this plan look reasonable?
• My CH tested from Pinch-A-Penny last week was 195ppm. Should I trust the CH result I got today?
• Liquid vs granular stabilizer?

Thanks all!

 

[mknauss]

Does this plan look reasonable?

yes

My CH tested from Pinch-A-Penny last week was 195ppm. Should I trust the CH result I got today?

yes

Liquid vs granular stabilizer?

Granular is fine, 1/4 the cost. Use the sock method.

 

[SQLGeek]

Thank you, sir! I will report back tomorrow.

Being in Houston, is a target CYA of 60-70 unreasonable? I figure I'll work up to it so I don't overshoot.

 

[mknauss]

I would not go that high without a SWCG. Target 50 ppm and see how that maintains your FC.

 

[SQLGeek]

Perfect, thank you. That sounds reasonable.

 

[SQLGeek]

Today's test results:

Latest Test Result Summary:
FC: 0.5 (21 minutes ago)
CC: 0.0 (21 minutes ago)
pH: 7.8 (21 minutes ago)
TA: 90 (21 minutes ago)
CH: 350 (yesterday)
CYA: 30 (yesterday)
TEMPERATURE: 90° (21 minutes ago)
CSI: 0.37 (21 minutes ago)

Disappointed to see FC down to 0.5. CC of 0 was good to see though.

I added 3 qts, 2 cups of 10% LC about this time yesterday. Per PoolMath, I added the same amount today just now. I will test FC tonight to see what it is at to see if I have my numbers right as far as pool volume.

I also added 15oz of MA yesterday evening to target a pH of 7.4. I wanted to work down to see how the pool reacted. It did go down to 7.8 but interestingly, TA remained the same. I am going to add 35 oz of MA tonight per PoolMath targeting 7.2 to see what that does.

Thoughts on this approach?

 

[mknauss]

You are losing too much FC. Either you have organics or you need your CYA a touch higher. What does the water look like?

Your FC needs to not fall below 3 ppm with a 30 ppm CYA.

 

[SQLGeek]

Water seems clear to me and not cloudy. I haven’t noticed it getting cloudy either.

I am wondering if I didn’t add enough LC yesterday.

I did buy 4 lbs of CYA. I was going to put the recommended amount in a sock per your comment to get to 50.

I will perform an OCLT and see what happens. I wouldn’t be surprised if I had organics since my chlorine has been low.

Brand new pool and I might have to SLAM it already.

 

[SQLGeek]

Tested again. About 40 min later. No more sun on the pool at all and won’t be for the rest of the day. FC 6.0 on the nose. No CC.

So looks like I’m about right with pool volume.

I went ahead and also added 35 oz of MA.

Will test FC again tonight. The testing is kind of fun.

Oh and I have a Speed Stir arriving tomorrow.

 

[SQLGeek]

Tested again tonight. FC was 5.0. Guess I need to raise CYA some and then SLAM. Will test again in the morning.

 

[SQLGeek]

Tests this morning before sun rise:

FC - 4
CC - 0
pH - 7.4

Looks like I’ll need to SLAM.

Will figure out how to suspend a sock in front of a return today to get the CYA in.

For now I’ll top off the chlorine to get through the day.

 

[Newdude]

Looks like I’ll need to SLAM

You lost 1 which fails. But you’re also new to this so it’s possible that one or two of your drops weren’t perfect. SLAM today to keep the upper hand if it’s algae. When you do your OCLT tomorrow, Slow it down. Slow gentle squeeze from a completely inverted bottle so that gravity makes perfect repeatable drops.

All new testers have a certain amount of nervousness to them, but you have plenty of time to do the test. Nothing is gained by trying to get it done in 9 seconds instead of 45.

For now I’ll top off the chlorine to get through the day

Either way, stay on top of it.

Will figure out how to suspend a sock in front of a return today to get the CYA in

Also great either way the FC test goes

 

[SQLGeek]

Appreciate the advice and encouragement!

I have been trying to be diligent in holding the dropper vertical, letting the drop slowly fill and letting gravity do its thing. I think I’m getting the hang of that.

The big FC reagent bottle barely needs any squeezing right now before a drop will come out so I am finding I need to slow it down a bit to ensure one full drop at a time is coming out.

My test results after adding the chlorine have given me some confidence in both the testing process and the amounts I am adding so that is positive at least.

 

[Newdude]

My test results after adding the chlorine have given me some confidence in both the testing process and the amounts I am adding so that is positive at least

You got this !! Keep in mind too that some extra FC never hurt anyone while they learned. You have leeway all the way up to SLAM, but next to zero leeway when you hit minimum. Sure it’s true that with more FC, some of it will burn off faster as a waste, but is 75 (?) cents a day worth it for some safety net to you ?

Once you know your pool and how it responds like the back of your hand, not only can you dance the fine line of adding the absolute least that you need, but as a matter of fact, I’ll applaud you defiantly doing an Irish Jig on that line if you choose to do so. Look AT you go……. You crazy S.O.B !!’ Lol.

Life pulls you away from the pool at times and events happen during those times. Big storms or incredibly hot / high UV days. They sneak in the moment you lapse. Murphy’s is in full effect here.

I started with the safety net of FC and it worked so well I never stopped. Food for thought.

 

[SQLGeek]

You raise an interesting point. I could target 8 for my current CYA which would put me a 2 PPM over the recommended high but under the SLAM of 12.

Of course, I need to work out my CYA levels and SLAM but it's something to bear in mind post SLAM. Fortunately LC is fairly inexpensive at Pinch a Penny but it will definitely need to be worked into my monthly budget. I have two 2.5 gallon jugs now so I can ensure I always have a supply of it at home. Shame I have a big bucket of trichlor pucks that won't be used. Sunk cost of ignorance I guess.

So much to learn. This is on top of starting a new job last week!

Oh I also updated my signature with my pump and the fact I have a UV light as well.

Another thought that just crept in, would the UV light contribute to Chlorine loss? Do I need to adjust my expectations or additions of Chlorine to compensate for this?

 

[Newdude]

could target 8 for my current CYA which would put me a 2 PPM over the recommended high

*over the recommended target range.

the fact I have a UV light as well.

Commercial systems, particularly for indoor public pools can do well. The rinky dink residential pool versions don’t produce a fraction of what the sun gives you for free. And they burn off some FC that passes through them. You’d be best served unplugging it.

Don’t feel too bad about it though. Many builders have it added in to their packages and removing them at build time doesn’t lower the price accordingly.

 

[wireform]

Don't add to the CYA till you're sure you have no organics in the water. A OCLT will let you know that. If you have lots of sun slamming can be a hassle with the uv robbing some chlorine. Make sure you have minimum 30.

 

[SQLGeek]

You’d be best served unplugging it.

Don’t feel too bad about it though. Many builders have it added in to their packages and removing them at build time doesn’t lower the price accordingly.

I'm wondering if the UV might be giving a false positive on the OCLT? I will see if I can figure out how to turn it off without voiding my warranty.

Don't add to the CYA till you're sure you have no organics in the water. A OCLT will let you know that. If you have lots of sun slamming can be a hassle with the uv robbing some chlorine. Make sure you have minimum 30.

My CYA level appears to be under 30 based on the fact the dot never fully disappeared when I tested and I ran out of water between 20 and 30. It appears I failed the OCLT so I should SLAM but my CYA seems to be under 30. What should I do?

 

[wireform]

20 ounces for your pool should give you 10ppm rise in CYA so if your not quite 30 but over 20 give 1pound of stabilizer and begin slam immediately, not necessary to wait.

 

[Newdude]

I'm wondering if the UV might be giving a false positive on the OCLT?

I believe it’s a positive false……. Or a would that be a false false ? Oh man !! Now my brian hurts. THANKS !!! But yeah, if the unit ate 1 FC you may have failed when you passed otherwise.

I will see if I can figure out how to turn it off without voiding my warranty

I believe the units simply unplug from their power source. Not sure if it’s an outlet, automation or a another controller, and it may be a twist-and-pull, but you should be able to easily pull the wire.