Help with alage or some stain along with low chlorine

[jeffdw]

I have been battling what I believe was mustard algae, since late June 08. I came home from vacation to find chlorine about zero and brownish powdery substance all over one side of my plaster pool. I brushed and shocked only to have the powder substance come back a couple days later but not as bad. I treated with polyqort 60 and shocked some more. A water test during this time showed high level of phosphates around 1000 and CYA over 100. I started using non-stabilized shock and treated for phosphates. Water had been clear but unable to hold FC, and the brownish powder stains kept appearing around 2-3 days if I did not brush. After brushing I could still see slight brownish stains in the pores of the plaster, while snorkeling underwater. They would get a little lighter by scrubbing with wire brush or stone but will not go away. They are only on the sides, but few places close to bottom.
So, a couple weeks ago I consulted my pool store and they advise to treat with yellow treat, which I did two treatments and supershock to no avail, alage like stains came back, and pool still couldn’t hold FC and CYA was still running high, even after draining a little and refilling 90-100.
Since that didn’t work they advise to try Banish fro Bio guard since it is copper base and would kill other algae as well. Did that last Thursday, along with shock, and was also told to raise chlorine levels to at least 10 and hold till stains algae disappear. However, after about 20 pounds of Bio Guard Burn Out my pool will not hold FC and CYA is still at 110. I also should mention that I have quit using pucks. I am unable to even get my water up to 1ppm chlorine let alone 10. Plus my water turned lime green after all the shock, but then went to milky blue by next day and by third was pretty clear.
Another pool store lady who actual came out to look at pool for free and as not been trying to sell me stuff advised just to be patient and let everything filter out. Then start liquid chlorine treatment tonight (3gals), and take reading tonight and in morning to see if water will hold FC. She doesn’t seem to be worried about the CYA levels having any affect on the pools ability to hold chlorine or any of the other junk that I have added to pool. Says if pool doesn’t hold over night that we will try non-chlorine shock, to break whatever is locking chlorine.
I am looking for any help to identify my algae and/or stains, and chlorine problems. This is my 4th year for the pool and have never had any problems, like this.
Here are my readings as of this morning. My pool is roughly 27,500, with D.E. Filter, had nature2 cartridge but took it out a couple weeks ago, also have electric heat pump.
Attached is a picture from above the water of some of the spots along the water edge this was take last week, after two days of no brushing.

FC .4
TC .6
CC .2
Ph 7.4
Hardness 260
Alk 117
CYA 110
Copper .35
Iron 0
TDS 300

Phos 300
Borate 30
Nitrate 15




Thanks!!!!

 

[Nasty90]

Are you closing your pool soon? Try a 4" wide stainless brush for those little dippets in the plaster. I you had mustard algae, you need to service the sand tank. Its prone to some of your water problems. Mustard spores are a beotch... If the sand older than 4 years replace it or clean the filter media.

 

[duraleigh]

Hi, Jeff,

Welcome to the forum. My first recommendation would be to disregard the advice of the pool store. Not intentionally, I'm sure, but you are being given bad advice. As soon as I see "chlorine lock", the flags go up.

You have two primary problems...both related.

1. Your CYA is w-a-a-y too high. You should be in the 40-60 range in a manually chlorinated pool. Tell us where you live and when you're closing your pool and you'll get good advice on the best way to correct it.

2. Secondly you have virtually no chlorine in your water....it is being consumed by algae and will continue to be until you kill all the algae. You need to shock your pool with chlorine (only). Just how much chlorine is suggested will dewpend on your answer to how best to fix your CYA. Post your response to the first issue and we'll go from there.

Your other numbers are fine and the filter is irrelevant to your issues.

 

[jeffdw]

I live in northern, Virginia. Fredericksburg to be exact.

I have a pool heat pump so generally don't close till end of Oct.

However, I just want to have pool swimmable and safe for my daughter's birthday party this weekend. Then will close next weekend, say first week of Oct. I tired of messing with it but want to have it cleared up for winter. I won't be able to sleep otherwise!

The low chlorine levels may also be do to the fact that I pulled all the pucks outs due to the high CYA and was just shocking.

My water was down to bottom of title line from backwashing a couple times last week, so I drained a few more inches and filled backup to middle of tile line. Hoping to dilute a little of the CYA.
I also dumped in 3 gals of liquid shock (12% kind) last night. After an hour the reading was about 6. Three hours later was about 4.5. (11:30PM)

I check it this morning about 0530am and was still holding @ 4.2. Was using my electronic Aqua Check. OTO show in the 3 to 4 range also.

I am hoping the levels will still be holding when I get home.

What should I do next?

A lot thinks I have read with CYA levels of 80-100 FC should be in the 8-10 range. Is this correct?

I can I insure pool will be safe to swim this weekend? Followed by making sure algae will be killed before closing?

Thanks for your response and help!

 

[chem geek]

So long as you can keep the FC level up and not let it drop very low, then the pool will remain sanitary, though the presence of algae will make it unsightly and will continue to consume chlorine. If you have a way of doing a relatively quick partial drain/refill, then that will help to lower the CYA level. You could then shock the pool with chlorine (you should lower the pH to around 7.2 before you shock since you'll be adding lots of chlorine) and closer to the weekend let the chlorine drop some to around 10% of the CYA level which is fine to swim in for the party, but monitor the FC level carefully to make sure it doesn't get too low too quickly. You should order your good test kit (the TF100 from tftestkits.com here, for example) and you will get it fairly soon.

Richard

 

[jeffdw]

Ok, got home around 5PM and there was only a trace of chlorine in the pool. Is it common for the liquid chlorine to dissipate that quick during the day? It was sunny in mid 70s and I keep a solar blanket on. I started with around 4ppm @ 5:30am

Any case I added 5 bottles of regular 6% percent bleach…I don’t know what else to do to keep the chlorine up and not add any more CYA.

Also, there is no sign of algae, the water is not "unsightly" it is clear...not sparkling clear but clear and always has been. I only get these algae or stains whatever it is on one side of the pool.

I have not seen any since last Wednesday, but I have been brushing everyday.
But like I said earlier there are slight brownish stains that can only been while in the pool with a mask. Are these algae roots or something else?

The pictures I posted where before brushing off. The stuff in the picture brushed off but leaves slight brown stain.
They do not brush off with wire brush.

To answer some of the other question, I have drained some of the water. I do have a wire brush, and I have DE filter not Sand.

What to do next??

 

[chem geek]

The only time you get rapid chlorine loss during the day and not at night is if you don't have any CYA in the water in which case the chlorine rapidly breaks down during the day. This isn't your case since your CYA level is very high. If you add chlorine after the sun goes down, then see if there is any FC drop overnight. If there's more than a 1 ppm drop, then the chlorine is fighting something in the pool and it's probably the mustard/yellow algae "brown dust" at the bottom and shady sides of the pool. That's what I meant when I said algae -- the brown dust.

5 bottles (presumed to be 96-ounce or 3/4 gallon jugs) of 6% bleach in 27,500 gallons would raise the FC by 13.5 ppm. How are you testing your chlorine level? If it's a DPD chlorine test which is the one where you add 5 drops of indicator and then compare the intensity of pink/red to a standard, then this kind of test bleaches out above 10 ppm FC so in fact you might have a high FC level in the pool right now. That would be my best guess at this point and is why you should really get yourself a good test kit that has a FAS-DPD chlorine test since it will not bleach out, can measure accurately to 0.2 or 0.5 ppm (depending on sample size) and can measure up to 50 ppm. In the meantime, you can try diluting your pool water 4:1 by mixing 1 part pool water with 3 parts tap water and seeing if you then get a chlorine reading (the tap water may have a chlorine level, but probably not above 1 ppm -- you can test your tap water separately to see the baseline chlorine level for your dilution test). Note that your AquaChek may be using a DPD chlorine test. You said you also had an OTO test so can use that to see if there is a high chlorine level since this test will not bleach out.

By the way, the BioGuard Banish algaecide you used has copper in it so you might get some staining when the pH gets high (such as when shocking with chlorine). The BioGuard BurnOut is either Cal-Hypo (BurnOut Extreme) or Lithium Hypochlorite (BurnOut 35).

So let us know what the OTO test shows -- does it also show no chlorine? If so, add more and note what the loss is overnight.

Richard

 

[Nasty90]

Algae always have it's day... It sounds like the growth of spores were really large. Brownish/red in color is dead algae. I can suggest turning your pool off, buy one or two pounds of heavy granulated chlorine shock, get some rubber gloves & broadcast the shock over the stains. Let the shock to sit-up for 10 the 15 minutes before brushing the stained areas. Between 6 to 8 in the evening is the best time to service your algae problems.

 

[jeffdw]

I fell asleep before I could take a reading last, as I didn't get a chance to add the bleach till around 830PM. Between kids soccer, football, homework, and real work…not enough hours left for pool.

How long should one wait before take a reading after adding the bleach at night?

This morning (530am) my AcuCheck Electronic tester showed 7.5, and OTO drop test was in the orange color range indicating 5 or above. So, I’ll see what it says tonight.

Yeah, I know I got to get a better tester...can't find one local for immediate use, so will have to order one for next year.

According to the thepoolcalculator.com. 5-96oz of bleach or 480oz should have produced 8.4 FC, assuming I was at zero...is this not correct?

I also thought my strips were bleaching out, but the OTO would show a faint to light yellow i.e. .5 to 1. And a pool store pinpoint reading would say the same thing. I don't think it's over chlorinated.

I have also done the directed shock spread down the sides of the pool where the stains where and scrubbed with wire brush, several times. Did not go completely away.

The confusing thing is I don't have any dust building up on the bottom or stairs; the water is not green or brown. There is nothing being kicked up when I bush a brush across the bottom. You can't even see the brownish stains unless you are in the water. I not even sure they are still there; I will have to try and get in tonight to inspect.

So, should I just keep hammering with bleach and try and maintain 8-10ppm, given a CYA around 100?
How about shock, how much, how often, what kind?
Pool lady is recommending hitting with non-chlorine shock and then another 3 gallons of liquid shock.
Should I be worried about clearing this up before closing or just start preparing for closing and partial drain and start over in the spring? As mentioned what to at least get another weekend or two out of the pool. But now I worried something else is growing, if the chorine won't stay.
Thanks for all your inputs?

 

[JasonLion]

The OTO test never bleaches out. If OTO says the chlorine level is low then it really is low.

Your CYA level is very very high, which means you either need to lower your CYA level or use way more chlorine than you have been using. With CYA at 110 you should be raising FC to at least 26 to shock the pool, and keep it up there until you don't lose any FC overnight. That is much simpler to do with a FAS-DPD chlorine test. You can use dilution with the DPD test, but you lose a lot of precision.