Brown stains....trichlor puck works

[Tom87GN]

I have a vinly liner pool, 30,000 gallons.

My shallow end has developed a ton of light to dark brown stains that do not rub off.

I tried the Vitamin C test with no luck.

I then tried the trichlor puck test, left it on the bottom in a sock for about 15 minutes, and it cleared the stain up right below the puck just fine.

My FC and TC levels are in the normal range currently. My PH is a bit high, so I just put some muriatic acid in the pool to try to help that out.

I use liquid chlorine (12.5%) mainly and do not like to use the trichlor pucks as they introduce CYA slowly, of which mine has always been on the high side. The cheapo test strips tell me my CYA is "high" at around 150 or so.

Given that info, should I throw a ton of liquid chlorine at this staining problem to see if it will go away? I usually put about 4 gallons of the 12.5% in to keep the FC and TC levels steady, but I have a bunch so I could dump 10+ gallons in it if everyone thinks that's what I should do.

I hate these stains, they are very ugly and frustrating. Any help is greatly appreciated.

 

[Richard320]

Welcome!

We don't recommend random doses of anything. Especially not huge random doses.

Keep the FC between minimum and shock level for a couple weeks and they should fade away. They didn't develop overnight, they won't fade away overnight, either. You determine the chlorine levels based on the CYA level of your pool. pool-school/chlorine_cya_chart_shock You DO have a test kit, don't you? Strips don't count.

If you haven't ventured in there, I'd recommend studying Pool School. Steady, daily doses of chlorine bleach work better than a 4 gallon blast every few days.

 

[Tom87GN]

Thanks for the quick reply Richard.

I can be patient and introduce smaller amounts of chlorine each day while keeping the levels up as you state.

I am in the process of getting a good testing kit, you got me there! I know that I need one, I just haven't gotten it yet. No excuses here.

We have four (4) in floor pop-ups that work continuously and I leave my equipment running 24/7. The pool stays very clean this way.

The weird thing about these stains that I have is that they are all concentrated around the floor jet that is closest to my stairs in the shallow end of the pool. They are in a "fan" pattern scattered out from this one floor jet almost like it broadcast some sort of debris that stained the liner. The funny and weird part is that there are no stains that are close to this particular floor jet, they are all out about 2-3 feet away from it but in a circular pattern around it.

Anyway, I'll follow your advice and see how that work over the next week or two. I'll keep adding in chlorine to keep the levels higher than I usually do. Apparently my high CYA levels (those Dang trichlor pucks got me before I got smart and started looking at this forum) are what is tricking me into thinking I have enough chlorine in the pool. I know how to get rid of the CYA.....by draining the pool. I don't want to have to do that if I don't absolutely have to though, as it costs huge $$$ around here to do such a thing.

Thanks again.

 

[duraleigh]

Where is "around here"? Most municipal water seem to cost around $5/1000 gallons....how much is yours?

 

[Tom87GN]

Where is "around here"? Most municipal water seem to cost around $5/1000 gallons....how much is yours?

My water bill (sewer, water, fees, taxes, more taxes, unnecessary taxes, etc.) is almost $200/month and I'm NOT filling up my pool.

The last time I had to fill it the cheapest way for me was to have the pool company do it from the fire hydrant next to my neighbors house. That cost me $650 and they have an agreement with the city and a lower rate if they meter how much they use at the hydrant.

Location = North side of Indianapolis.


If it only cost me $150 to fill my pool, I'd do it in a heartbeat.

 

[duraleigh]

Stunningly high.

 

[Tom87GN]

Stunningly high.

Yep.....the issue is that when you use an enormous amount of water, they raise the sewer side of the bill exponentially as well in efforts to provide better service to the paying customer. :grrrr: Then guess what goes up too......TAXES. It all adds up to a painful experience.

I even called them on it once just to see what the explanation for it was. I think it would have been much easier for the gal to just say "because we want all your money" rather than what she told me. It added up to a bunch of bull hockey and I was just more mad for asking the question.

Now, if I hook my hose up to my neighbors house it won't cost me as much........ :lol:

 

[Tom87GN]

Okay everyone.....I finally got my TF-100 test kit.

My brown stains are still there. I have confirmed that they are of the organice type, because the "puck test" wiped it out in the area where the puck was sitting for approximately 20 minutes or so.

Here are the numbers after testing everything but Calcium (I have a vinyl liner pool):

Ph = 7.8
FC = 27
CC = 2
TC = 29
TA = 280 (initial color of the solution was green/blue and it took 28 drops of the R-0009 to make it turn yellow.....I did wipe off the tip of the bottle after each drop with a wet paper towel as required)
CYA = over 100 but can't be measured with this kit effectively (the black dot in the bottom went away before I got to the graduate line for 100, which is the highest that this kit would read)

I have attached a picture of the CYA tube test to show where it ended up and when the black dot disappeared from sight at waist level.



Any thoughts? I know I need to drop the alkalinity and the CYA. I know that the only way to drop the CYA is to remove water and add fresh water.

The screwy thing is that the water is crystal clear in the pool. No one gets sick or has irritated eyes or anything other type of affects while swimming in the pool. I just have these brown organic stains on the bottom of the pool in the shallow end that will not go away.

Thanks in advance for any constructive criticism.

 

[Richard320]

The CYA tester graduations are not equidistant. What looks like 150 may be 180 or even 200. What you need to do is mix 50-50 pool water and tap water as precisely as you can and then use that solution with the R-0013 to run the CYA test. Double your results. That will be close.

Secondly, that CC reading looks very high. Have you been using any yellow-out or similar MPS "shock" products? They will give a false high reading.

 

[Tom87GN]

Secondly, that CC reading looks very high. Have you been using any yellow-out or similar MPS "shock" products? They will give a false high reading.

I have been using 12.5% pool shock only....no other chemicals.

You had recommended earlier in this thread that I begin "cholorine maintenance" by adding small amount of chlorine to the pool every day, rather than adding 3-4 gallons each week or so.

I have been adding a gallon or two to the pool each night for about a week. The stains appeared like they started to subside, but then just came back full after i suspended the "chlorine maintenance" I was doing. I wanted to stop adding anything to the pool until I got the TF-100 kit.

 

[duraleigh]

First, you have a very good grasp of the chemistry of your pool.

There is no CYA test that accurately reports anything above 100. If you are curious, you can put in 1/2 pool water and 1/2 tap water then double the results. The accuracy is not as good when you do that but it may be helpful.

Your cc result of 2 is a bit troublesome. However, given the clarity of your water, I would just elevate the chlorine for a few days and see if that CC's test doesn't come down to .5 or less. If not, you probably need to shock.

TA of 280 is pretty high but if your pH is staying relatively stable, I think I would just leave TA alone...it'll come down on it's own normally.

What is the pH and TA of your fill water? Are you filling from a municipal supply?

 

[Tom87GN]

First, you have a very good grasp of the chemistry of your pool.

There is no CYA test that accurately reports anything above 100. If you are curious, you can put in 1/2 pool water and 1/2 tap water then double the results. The accuracy is not as good when you do that but it may be helpful.

Your cc result of 2 is a bit troublesome. However, given the clarity of your water, I would just elevate the chlorine for a few days and see if that CC's test doesn't come down to .5 or less. If not, you probably need to shock.

TA of 280 is pretty high but if your pH is staying relatively stable, I think I would just leave TA alone...it'll come down on it's own normally.

What is the pH and TA of your fill water? Are you filling from a municipal supply?

I think I may have made a mistake on the CC value. It took 2 drops to make the color change correctly. 2 drops X 0.5 = 1. So I guess my CC value is 1.

When I fill the pool with water, I use the municipal water through a garden hose. I have not checked that source for pH or TA, but then again, I don't use much either. We don't drain our pool each season, so I only fill it for a couple hours a few times a season to keep the water level up where it should be.

Is the recommendation to elevate the FC to even higher levels than it is currently to try to get rid of these stains? FC at 27 seems high to me.......

Does the high value of CYA have anything to do with these stains?

 

[chem geek]

Does the high value of CYA have anything to do with these stains?

Indirectly, yes. The high CYA didn't cause the stains. Since they are organic, they are probably caused by some debris such as leaves or other decomposing material. Normally in a pool with a proper FC and CYA ratio, such temporary stains or oxidized by chlorine so fade away. In your pool with a CYA that is too high, that doesn't happen unless the FC is significantly raised, but in your case it would be better to do a partial drain/refill of the pool to lower the CYA level so that it becomes more manageable.