Yellowish Brown formations on wall

[JCJR]

I have yellowish Brown formations on diamond brite wall. They are not stains but looks like something is growing. They are hard, small irregular shapes, and do not brush off. I have tried a chlorine tablet but that does nothing and have rubbed vitamin C tablets and that seems to break it up some of the spots but not all of them. It does not dissolve it. I am assuming it is metal.

Am I right is assuming it is metal, and what kind?

How did I get these? I do have well water for my sprinklers but would a small amount of overspray cause this? I was thinking that during the 4th of July holiday, my pool had some spent up fireworks fall in from being air borne.

What are the procedures to get rid of these stains/growth and prevent them from appearing?

BTW, new pool finished in April and PH still going up, I add about 1.5 gals of muriatic acid weekly. My PH has been above 8.0 a couple of times and my TA has been around 70 for the first couple of months. My CYA had dropped below 30 after emptying water a couple of times last month from the rain.

My numbers now are:
CL 3
CC 0
TA 80
PH 7.6
CH 260
CYA 45
Salt 1800 (I use BBB)

 

[Guest]

Sounds like they might be scale deposits.

 

[duraleigh]

Yeah, I think scale as well although that's a guess and I'm puzzled by your color description. I assumed most scaling was white/grey but I don't have enough hands on experience.

If it doesn't brush off and is not slimey to the touch, you can pretty much eliminate any organics. Iron and copper would be pretty much eliminated as well (No, the blow by from your neighbor is not significant enough and copper stains would be very dark).

Iron is a possibility but I would not assume that.......a test form the pool store will reveal it.

Since your pH has been high, scale makes the most sense. Find a way to get some muriatic acid onto a small stain (maybe with a syringe). If it quickly changes, it's scale (calcium).

Post back your results and several folks here can suggest a course of action for removing it.

 

[JasonLion]

Both iron and common organic debris can turn scale deposits yellow/brown. The vitamin C had a partial effect so I would guess a mixture of iron and scale, mostly scale.

 

[JCJR]

duraleigh,

I actually put muriatic acid in a squeeze bottle and tried to apply it but it did not remove anything. I do not think the acid was on the stain long enough to do damage. How long does it need to sit on the stain? Would it dissolve/remove on contact immidiately from the acid?

All,

How can I tell if it is scale deposits, and how do I get rid of it?

 

[JCJR]

I put muriatic acid in a pvc pipe and held it over the stain and it fizzled away, it also left the Diamond Brite a little darker, I have the blue regular color and the pool is a little white. With the information WeaterBear, Duraleigh and JasonLion gave me I think it is scale.

I also wanted to add Borates to my water so I have 19 boxes of 20 Mule and 5 gals of Muriatic acid standing by. Should I add the acid to get to 6.8 and turn off my pump and let it sit. If so, how long and when should I start to bring it back up with the 20 Mule Borax?

 

[duraleigh]

I'm out of my pay grade and have no personal experience but, short of draining and an acid wash, I believe the common sense procedure would be to carefully control pH down at 6.8 (lower might be fine....I'm just not sure) and keep it there with the pump running it's normal cycles.

The idea is prolonged exposure of the scale to a slightly acidic condition which will eventually result in it dissolving into solution. My thinking is this might take some weeks......it's certainly not going to be quick. The lower you think you can operate your pool water, the quicker the process will probably be.

My approach would be to operate the pool as normal (go swimming, etc) but hold the pH CAREFULLY between 6.8 - 7.0 and brush that scale often further exposing it to the mildy acidic pool water.

Again, please take my advice with a grain of salt.....it makes sense to me but others with more experience may have a much better plan.

I'm not sure what affect borates would have....I'd be tempted to leave them out of the pool for now.

 

[Guest]

Duraleigh gave you good advice. The only thing I would add would be to brush the pool regularly with a combo (stainless/nylon) brush. It can take weeks for this to work. You might also want to look for a scale control product (Ace Hardware sells one under their O-Ace-Sis brand as Calcium Harness Reducer) and add that to your water also.I would hold off on the borates until after you tackle the scale deposits since the initial additon would make your pH rise and might make it worse. It will also act as a pH buffer so it will make it more difficult to maintain the lower pH in your water that you need right now.

 

[JCJR]

Would the combo brush (stainless steel/nylon) scratch my Diamond Brite?

The weird thing is my CH is 260, I thought that number is slightly lower for my pool. Is there a way to do an acid wash with out draining?

 

[Guest]

United Chemical sells a no drain acid wash kit. I really don't know much about it.