Little brown rust spots on fiberglass pool...

[mknauss]

Ok I think I have a serious calcium hardness problem. I have been noticing it is taking more and more bleach and muriatic acid to keep things at the right levels. There is now what looks like brown scale/mineral deposits appearing and they wont brush off.

The other day after adding some water (we lose about a couple inches a week from the heat) I tested my water and the CH was almost 1000. The tap water around here is insanely hard I guess.

So how am I supposed to lower the CH? I read that the 'pour in' solutions don't work, and the only way is to refill with fresh water, which I COULD do (since it evaporates so fast), but I need a way to lower the CH in my TAP WATER now too..

Your water source in most of southern Nevada is the Colorado River. It's natural CH is about 250ppm and TA 140 ppm.

The only way to reduce CH in pool water is to replace it with water with less CH or hire a reverse osmosis service that comes to your pool and runs the pool water through a RO unit. They still will need about 1/4 to 1/3 new water and cost ~$750 to $1000.

If you have a water softener that you can pipe to use as make up water (used due to loss from evaporation) you can stem the cycle described above.

Do NOT buy any internet potions that claim the remove calcium. They do not. Some tie it up for a while so they do not scale but none remove the calcium from the water.

 

[mcaswell]

So Strange...why in the deep end only...insane.

Same exact issue here, identical looking spots, and ONLY in the deep end... been noticing them growing in number over the past several years. When I tested with Vitamin C tablets, they did seem to diminish, but they come back. I'm assuming it's metal in the water, but it's really fascinating that they only occur in the deep end, and that the staining takes the form of scattered little spots (with a bit of a "hole" in the middle of them) that increase in number but not really in size.

I know nothing about the chemistry of metal in water, but when present does it consist of tiny suspended particles? If so, is it possible for these particles to settle when the pump is off at night, and because of the slope of the bottom, they end up drifting all the way down to the deep end? That doesn't really sound feasible, but I'm just throwing out ideas.

Alternatively, could the higher water pressure at the bottom of the deep end have something to do with it?

Regardless, I assume the only solution is to somehow remove the metal from the water.

 

[toofast]

So I wonder how we figure out exactly what this is I seem to have more appearing and once again so bizarre it's only in the deep end.....

 

[Winger 03]

So same situation with me..... Never a problem in my 9 year old fiberglass pool. Last year 2 things happened nearly simultaneously.....
#1) The original pool builder jack hammered and removed the entire coping and poured a new one.
#2) I added 1 bag of what I now know what to stay away from - Clorox Pool Salt.

Shortly thereafter, I noticed 3 or so smaller than a pencil eraser stains that looked like rust. What was interesting to me was that they were not raised or depressed. They seemed even with the surface of the pool. They were in the deep end and were hard to get to with a big blue eraser thing at the end of a pool pole. Upon opening this year, I notices that there were 3 or 4 more - all about the same size (and the older ones did not appear to grow). Fortunately one if in a very accessible area that I can experiment on.

In order I am going to try the following:
1) big blue eraser again though I do not think this will help
2) crushed up vitamin C tablets
3) triclor puck which I understand I can get a 1-pack at a pool store or Walmart

Any other suggestions, or am I wasting my time and it is possibly something else? Typically I am right in line with TFP chemical levels using my TF-100 (and have been doing so since I installed the pool - I know no other way). Is it possible that this is cobalt?

Many thanks!
Jim

 

[Household6]

We tried the vitamin C and it helped. Then used a puck. I wasnt there to keep an eye on it and it turned our paint a shade lighter in the area it sat on. Did help with the spot. My suggestion would be to break the puck up and only use a small piece.
We repainted shortly after. It’s been 6 years and we haven’t seen any of the spots since.

 

[mcaswell]

I added 1 bag of what I now know what to stay away from - Clorox Pool Salt.

I wonder if that could be the common element here, as I too use Chlorox salt a few years back. Haven't used it again, but presumably once the metal is in the water, it would stay for a long time (with only small amounts being removed by splash out and draining after heavy rains). Noticed today that my number of spots is still growing.

 

[Winger 03]

I wonder if that could be the common element here, as I too use Chlorox salt a few years back. Haven't used it again, but presumably once the metal is in the water, it would stay for a long time (with only small amounts being removed by splash out and draining after heavy rains). Noticed today that my number of spots is still growing.

I think that is it, a small amount that is tough to get rid of. Better weather this weekend, I am going to try the Vitamin C tablet.

 

[Anthonyrusso3]

Has anyone tried the Jacks magic cobalt cure to see if it works

 

[Household6]

Has anyone tried the Jacks magic cobalt cure to see if it works

I haven’t. But in searching the forum I’m seeing it often works, but then they reappear a couple days later.

 

[rizzil]

I just wanted to add to this thread that I have these very similar sounding issues problems spots.

My chemistry is always been perfect and I never worried about CH once I saw the spots I tested CH which was 50 I bumped up to 150 with no apparent changes vitamin C or pucks do nothing.

Not sure what to do next but this is a relatively new pool and the manufacturer is not willing the comments yet it appears.

Those photos are from a 6ft depth best I could do.... and they're only in the deep end close to the main drain circulation should be very good.

Standing by with anything I can do to help both the original poster and myself

Any solution, have exact the same on my fiberglass pool, rubbing vitamin C or a chlorine puck does nothing...

 

[heidispool]

Was there ever a resolution to this problem? I have the exact problem. Tiny roundish rust looking spots with white centers. Have had this 20,000 gallon in ground fiberglass pool for 4 years and this summer is the first they've appeared. They are becoming more numerous and were only in the shallow end at first but now appearing in the deep end as well. Tried calcium, chlorine pucks, magic eraser, stain removers, metal remover etc. All to no avail. Thinking it could possibly be from weed control granules? its the only thing we can think of. We really want to fix this problem.

 

[p1zaul]

I am having the same issue, but they do come off with magic eraser, is there any way to get the metal out of the water off that is the cause