White film on water line

[JpoC]

A few details on the situation:
1. New plaster in the last 12 months
2. New Pool tile in the last 2 months
3. Fresh pool fill 2 months ago (after tile was done)
4. Levels all balanced great. (Local water district has low CH, so I've added to get on low end of range)
5. Never debris in pool, sun all day, no shade.

What I'm noticing (yesterday) is a white film along the water line on the pool tile. I quickly rubbed my finger on it and it seemed to come off, but I'll check again tonight. Is this Calcium? I highly doubt my pool magically increased it's CH in 4 weeks to start depositing.

I got rid of the pool guy, and part of the process was not using the liquid Chlorine he used and went to granular (ProPowder Plus - Leslies). I also have 2x Leslies 3" tabs floating around. (16,400 Gallons).

Water is crystal clear. I noticed that the chlorine has been stable for 1.5 weeks now, which is new...summer time it wouldn't last 1 week.

I am having to add MA weekly as my PH keeps rising.


FC - ~1.25
PH - ~7.5 (but is high every week, and I'm adding ~16-24 OZ of MA a week (using acid drop test)
TA - ~75-80
CH - ~280 (I'd have to recheck, I just remember that 3 weeks ago it was on the lower side of the "ideal" range)
CYA - ~70-75



Any Thoughts on what that white film is/was? (Pool pictured on attachment, b4 film showed up)



FC - Free Chlorine - A sanitizer which keeps your pool water safe and free of germs. Chlorine must be constantly replenished. (level depends on CYA)
PH - Acidity/Basicity - Needs to be kept in balance to prevent irritation and protect the pool equipment. (7.2 to 7.8)
TA - Total Alkalinity - Appropriate levels help keep the pH in balance. High levels can cause pH to rise. (60 to 120ppm, sometimes higher)
CH - Calcium Hardness - Appropriate levels help prevent plaster damage. High levels can cause calcium scaling. (220 to 350ppm, vinyl lower)
CYA - Cyanuric Acid - Protects chlorine from sunlight and determines the required FC level. (outdoors 30 to 50ppm, SWG 70 to 80ppm, indoors 0 to 20ppm)

 

[needsajet]

Welcome to TFP! Good to have you here

If the white stuff at the waterline comes off easily (e.g. wiping it with a wash cloth), it's probably just salt deposited after water evaporates.

Your numbers look fine except for FC which is too low for your CYA level. If the water is cold, you might get away with it, but eventually algae will start growing at that level. Here's the levels that will do the job: [FC/CYA][/FC/CYA]

If this is not a salt water pool with salt water chlorinator, then you might find that CYA level higher than necessary, but still manageable. If you're using dry chlorine products to provide the FC, that situation will get increasingly difficult to manage, and eventually unmanageable. Chlorinating liquid or bleach is the better option.

You'll have the best success with a reliable test kit, either the TF100 from tftestkits.net which is optimized for TFPC, or the K-2006C.

Nice looking pool!

 

[JpoC]

Welcome to TFP! Good to have you here

If the white stuff at the waterline comes off easily (e.g. wiping it with a wash cloth), it's probably just salt deposited after water evaporates.

Your numbers look fine except for FC which is too low for your CYA level. If the water is cold, you might get away with it, but eventually algae will start growing at that level. Here's the levels that will do the job: [FC/CYA][/FC/CYA]

If this is not a salt water pool with salt water chlorinator, then you might find that CYA level higher than necessary, but still manageable. If you're using dry chlorine products to provide the FC, that situation will get increasingly difficult to manage, and eventually unmanageable. Chlorinating liquid or bleach is the better option.

You'll have the best success with a reliable test kit, either the TF100 from tftestkits.net which is optimized for TFPC, or the K-2006C.

Nice looking pool!

Great, Thank you. No, this is not a saltwater pool. So, you would recommend liquid over the dry/granular Chlorine? I liked the "idea" of the bags as 1 bag/1 pound says it will treat 16,000 gallons (Leslies). If I buy bleach or liquid chlorine, is it about 1 gallon to do the same treatment? My FCL is probably more normal than what I stated. (The yellow test is pretty dark, I'll retest tonight) So, if it's not a Saltwater pool, what would that white residue be then? Sorry, if you already stated, but that would make sense if it was a saltwater pool....but mine is not.

Currently the water temp is hovering around 76-78.

 

[needsajet]

Sorry, should have explained. All pools have salt, often 1000 to 2000 ppm, which arrives with any common source of added chlorine. It accumulates over time, and is only reduced by things like splashout and backwashing along the way.

Yep, liquid chlorine is the way to go, because any dry form is adding CYA every time you add chlorine. Take a look at the bottom of PoolMath - 'effects of adding chemicals' - and try some additions with trichlor (most common pucks) and dichlor (most common powder). You'll see that CYA is added, and it's a fair bit because chlorine must be replenished regularly.

The OTO test (the yellow one) is reliable to detect the presence of chlorine, but not an actual number. Some TFPers use it for a quick dip to see if there's any chlorine at all. The FAS-DPD chlorine test is reliable (DPD powder to turn the water sample pink, and then FAS drop test which is an accurate indicator of the chlorine level).

 

[JpoC]

Got it! Thank you so much! That's exactly what it must be. I'll be making the switch to liquid as soon as the 3 bags of powder get used up. Thank you for your time!

Jeff

 

[needsajet]

No worries, glad it was helpful. When I started out with TFPC, this article was really helpful for me: TFPC for Beginners

Pool School is also valuable reading. Happy swimming!

 

[TXHeat]

Glad this was posted......I have been on TFP methods for a couple months now with great results for the clarity of the pool, algae, etc. Love the simplicity and ease of keeping my pool in balance and looking great. But I have had the same white film problem on the pool tile above the waterline the OP mentioned. I brought it up a couple weeks ago and was told a MA/water solution applied would do the trick. It didn't help at all, even at 3:1. Started at the suggested 5:1.

I've never had this problem before and wondering if the salt content in the bleach is causing it. Any other causes or methods to remove it? I've read elsewhere that CLR has worked for the same issue, but wonder if that's advisable.

 

[needsajet]

Staying on track with JpoC, just wondering if you have been using cal-hypo (calcium hypochlorite) as a source of chlorine?

Does the white stuff wipe off easily with a washcloth? If not and it's hard to remove, it may be calcium.

Yep, liquid chlorine is the way to go, because any dry form is adding CYA [Edit: or CH] every time you add chlorine

 

[emac]

Very nice pool! I think I have the same tile. I am no expert, as my plaster pool isnt even a year old. However, I have/had a similar problem. My CH was low and i added some calcium chloride to raise the level. Right after that I noticed much more deposits and I had to clean my Liquidator (liquid chlorine feeder) several times as it was getting plugged with a white scale. I added the right amount of Calcium chloride, thought I had it mixed well, etc. In any case, it took several weeks for it to get back to normal. My CH is about 350, I wish it were a little lower, and I wish I had only added about 1/2 of CaCL2. Live and learn. I probably should have asked TFP before I did anything , but I am the guy that reads the directions when I am cleaning up.

I ended up letting my water get lower than normal, putting some muriatic acid in a watering can, and using thick gloves and a steel brush I scrubbed every tile. I recommend a mask as well. Some of my deposit would rub off by hand but most needed some elbow grease.

HTH, and I suggest reading and asking here first. Unlike many forums, the people here are very forgiving!