Staining and Balance questions

[flipr]

First, let me say I've been using TFP since the pool was installed. Using poolmath spreadsheet with following settings

FC 11
pH 7.5 ( usually climbs due to waterfall, add acid weekly to reduce TA and pH)
TA 60
CYA 70
CH 300 (has been testing over 500, but comments here say to ignore)
Salt 3400

We have SWG installed. Couple months ago the FC had climbed to about 17 so we turned it off to let it drop in the cooler weather.

In our 3 years of maintaining pool we've ALWAYS been in the green on CSI, test weekly, only had 1 algae blum in first year, that was last time we SLAMmed.

We developed some staining, a rusty greenish color. I tried vitamin C, but evidently not correctly. Hired a 'stain guru' from the area, and he poured L-Ascorbic Acid Powder over the stains for 3 days, and they are gone.

Now he advises our chemical balance (and MA method of adding) likely were source of issue.
Regarding MA, we add weekly to reduce the TA. We pour in front of the only wall return we have, which is in shallow end. That's area where stains started. Also advised to add acid in the deep end. When we add CYA we put the bag in front of the wall return in shallow end as well.

He is recommending
pH 7.2 - 7.8
TA 90-110
CH 300
CYA 50
FC 1-5
Salt 3200

His numbers fly in the face of what we have been doing, but wondering if our balance was off so far it caused the staining?

I'd appreciate any input. Thanks so much.

 

[YippeeSkippy]

When you add chemicals, particularly the MA, do you brush it around immediately to mix in? I feel that's important as I don't want it to drop low and sit there.

Without any returns in the deeper end, I would add MA to the deep end and BRUSH! BRUSH! BRUSH! and keep the pump running for another hour.

Your TA at 60 is just fine. What is your pH when you're adding MA weekly?

Do you have any water features like fountains or such that are causing your pH to rise so much?

Follow the FC/CYA chart and base your FC on your CYA level. [FC/CYA][/FC/CYA]

Calcium will rise on its own due to evaporation of water....but being that you're in FL with frequent rains often filling and diluting pools, well...its not so common. So make sure you're not adding anything with calcium in it.

No algaecides or other potions have been added, right? Do you have iron in your water- sometime you can see it as rust in the toilet or lav

Maddie

 

[mknauss]

There have been reports of certain brands of salt leaving stains. Do you pour your salt in that area? How often do you add salt? I would think with your rains you might add it more than we here in the desert.

Take care.

 

[flipr]

THanks Yippee and mknauss.

No we haven't been brushing the MA, but we will start. And move to putting it in the deep end as well.
We do have a waterfall that wife enjoys, so that is always on while pump running. THat drives pH I believe.
It usually is in the 8 range, so we add acid to drop to 7 and keep the TA lower.
Staining was confined to shallow end and gunnite steps. We always add salt to deep end, so no, probably not staining from the salt.

No other potions or additions at all. We do have hard water, last time I drained most of the water I refilled with water softener water. But the CH keeps rising.
Don't think we have iron, toilets/sinks/shower all clear, no special filters in use either

 

[Texas Splash]

His numbers fly in the face of what we have been doing, but wondering if our balance was off so far it caused the staining?

I don't think so Phil. The fact his ascorbic acid treatment worked to remove that rusty/greenish color should indicate the stained area was attributable to iron. Lowering your CYA would have no bearing on that, and I doubt the MA did either. What you may want to consider is the water source. While we typically think city water doesn't have metals, sometimes they do. We've seen it happen before. You’re using a water softener which may be helping a little. But get enough iron there and combine it with an elevated FC level and/or pH and the colors begin to change. Avoiding excessively high FC levels, or the need to SLAM, is one part. The Chlorine/CAY Chart for an SWG pool (higher CYA w/ lower FC) should help in that regards. Keeping the pH in the low 7s can also help some pool owners who have iron. But I would follow-up on that water source for any iron content. They should be able to provide you with their annual water report. If any iron content is at >0.3, there's an increased potential for iron reaction to chlorine.

- - - Updated - - -

Do you ever see staining on your filter media? How about trying a white sock over your hose when you refill? Even tried that? I'd be curious.

 

[duraleigh]

If ascorbic acid cleared your stain, you had iron deposits....not algae

Control your pH (always in the 7"s) with muriatic.

CONTROL YOUR TA with the method described in Pool School

The iron probably still exists and will continue to be troublesome until you start using a sequestrant (and keep your pH out of the 8's) or change to a no-iron water source.

Are you using softened water to refill the pool?......that would probably solve your iron issues.

 

[mknauss]

Another item -- any way to shut off the waterfall unless you really want it on? Eliminating that aeration will no doubt significantly reduce your pH rise.

Take care.

 

[YippeeSkippy]

Along with the softened water Duraleigh mentioned, try to capture plain old rain water in the pool if you can. Some folks will drop their pool level an inch or so when they expect a good rain and then let the rain refill the pool. This would all be iron-free water. Win!

Maddie

 

[Swampwoman]

What's important to understand here is that you simply WILL NOT get metal staining without metal in the water. Period. So, you have metal in the water, and need to act accordingly. Eg. Metal Sequestrant.

Balance, in the way the so-called guru said, has very little to do with the staining, EXCEPT for the effect of allowing ph to run high at 8, which may cause the metal to precipitate.

I just wanted to reassure you that your parameters are fine and your guru is full of pool store/industry babel. But at least he was able to show you that ascorbic acid worked on the stain. That is the only fact worth keeping from your session.

 

[flipr]

Along with the softened water Duraleigh mentioned, try to capture plain old rain water in the pool if you can. Some folks will drop their pool level an inch or so when they expect a good rain and then let the rain refill the pool. This would all be iron-free water. Win!

Maddie

Thanks all, yes we collect all the rain water we can, but it hasn't rained much lately. Will try putting skimmer sock over hose end and see if we get discoloration.
Whole house softener, so the garden hose is softened most of the time. Have to bypass softener to get straight city water.

Will keep closer eye on FC and pH, its always been so clear didn't realize an issue until now. Maybe checking pH and FC couple times a week so we don't need such big swings with the MA

As for the waterfall shut-off, I've been told that valve is off limits, so we will test more often

Thanks all

 

[Texas Splash]

As for the waterfall shut-off, I've been told that valve is off limits,

I'm assuming those orders are from "Mrs Phil" and not a pool tech? :grin: