STAINS and CHEMISTRY

[rmklaw]

I need some advice. I have some streaks and stains in the plaster. The pool is about 18 years old. My water has been very stable with rock solid readings. I use Autopilot Total Control SWG. My latest readings are:

FCL 1.68
TCL 1.72
PH 7.4
ALK 50
CH 340
CYA 60
Phosph 250
Salt 2890
Temp 74

The PB says that the reason for the staining is low ALK and recommends that I increase it. I am worried about increasing ALK without knowing how that will affect everything else. I have used United Chemicals Red but did not remove the stains. Help please. Thanks.

 

[frustratedpoolmom]

That's nonsense. The TA is a little low but that would not affect the stains. You can add a little baking soda to raise the TA up to about 70. Learn to use the Pool Calculator to figure out how much Baking Soda to add.

I can tell you your FC is too low. Do you have your own test kit?

You can test stains a few ways, you can put a vitamin C tablet on the stain, if it's iron it will fade.
You can place a chlorine tablet on the stain, and if it fades, the stain is organic. Try both and post back with the results.

Also, if you could post some pics of the stains that would help too. Use a photobucket.com or similar host site to upload your photos. Holler if you need tips on getting the photos to show up.

How long have you had the stains, and do they seem to be spreading?

 

[SplashPoolsMD]

Streaks and stains are not going to magically disappear with just a slight adjustment in water chemistry unless they just suddenly appeared. If this condition happened over a period of time you will most likely need to take some more drastic measures. You may consider a standing acid wash or a drain and clean procedure. The person you need to contact is Randy Dukes at PoolFinishes.net. I have nothing to do with his company nor do I receive anything for this recommendation. He is one of if not the foremost authorities on swimming pool plaster. It is who we call when we have any kind of staining, streaking or plaster issue.

 

[bk406]

Ok now lets dont get too drastic here until we know whats going on. FPM has good advice. The vitamin C tablet held on the stain will tell us if its iron or not. If it's iron, it will disappear pretty fast. That would mean you have iron in the water at some point and it deposited on the pool surface. If thats the case, there is a pretty basic procedure one can use to manage that w/o a drain and wash, probably. An ascobic acid treatment can be done thats detailed really well in Pool School. If that doesnt work, it could be organic. As FPM said, holding a trichlor puck on it for a bit will lighten it up if its organic. Pictures will help a lot for folks on here to see the stain. If you will listen to advice here and follow step by step, a drain wash and refill most likely is not needed. Of course, in some cases, that could be the case, but thats down the road. It could be as simple as ascorbic acid treatment and adding a sequesterant.

And yes, out of whack chemistry can make a managable metal problem worse.

 

[Butterfly]

Streaks and stains are not going to magically disappear with just a slight adjustment in water chemistry unless they just suddenly appeared. If this condition happened over a period of time you will most likely need to take some more drastic measures. You may consider a standing acid wash or a drain and clean procedure. The person you need to contact is Randy Dukes at PoolFinishes.net. I have nothing to do with his company nor do I receive anything for this recommendation. He is one of if not the foremost authorities on swimming pool plaster. It is who we call when we have any kind of staining, streaking or plaster issue.

Frank, we don't generally get that excited about some stains

They're pretty common and usually easily handled by the forum member, based on recommendations of other members here on TFP.

You might want to spend a little more time in our Pool School, to include further reading, to really understand what TFP is all about.

 

[rmklaw]

Thank you so much. I will follow FPM's advice and test with both, vitamin C and the Chlorine puck. I will also take pictures and post them. I use two different test kits. The Taylor and also a LaMotte with electronic colorimeter. Readings are very consistent. As far as low FC, I have been running the SWG at less than 20% power. I will increase a little. Will report back.

 

[geekgranny]

You may consider a standing acid wash

What is the difference between a "standing acid wash" and the Ascorbic Acid Treatment?

Thanks, gg=alice

 

[JasonLion]

An acid wash is generally done with muriatic acid, which lowers the PH a great deal. Ascorbic acid does happen to lower the PH a little bit, but is used because it is a reducing agent, which reduces the oxidations state of the metals, allowing them to come off the surface.