Just bought a house with a pool-Black Algae and No Chlorine

gruve

Member
May 30, 2012
18
Deep South Texas
Hi all,

First day reading the forum... first post after a few hours of reading...

So we bought the house recently and just continued service with the existing pool company. After about 9 months of pool plaster beginning to flake (looks like the surface of the moon now), pool plaster turning yellowy brown (metal staining) - they pulled the metal stains out with some chemicals later or so they say, then it cleared up for a couole months this spring... now i'm seeing black algae spots that have spread across the bottom.

In my opinion, my pool service company is just terrible and is doing a horrible job, but to confirm this, I've decided to inform and educate myself. I don't want to be THAT guy that makes complaints with not basis or understanding of whats going on. So here goes nothing:

I've been doing some research and I think I did my homework on the TFP beginners guide, reading through it, purchasing the recommeded test kit, I'm still in need of gathering exact pool equipment info but it's dark outside and I managed to remember basic details, and now here are the test results -

FC - 0 to .5
TC - 0 to .5
pH - 7.6
TA - 70
CYA - 75
CH - 650(ish - it said to do it drop by drop but after 60 drops i was doing them several at a time... it turned purple around 60 drops and blue between 65-70)

My confusion is why I have no chlorine in my water when I know there's a bucket of tabs by the pool, 3 dispeners floating (not sure if anything in them), and black algae growing on the bottom, oh and some green/yellow on the walls today.

Do i just need to add a bunch of chlorine or is something (ie my pool guy's lazy/not doing his job) or is there something causing the water to not "hold" chlorine?

I noticed the CH value is higher than the recommended 150-400 listed in the test manual.

Hope i gave you all the info I was supposed to.


On a BBB question - doesnt bleach have a really high pH (thinking back to my chemistry classes years ago) and doesn't that raise the pH of the pool? Wouldn't that be a bad thing? Thanks again!
 

Isaac-1

TFP Expert
LifeTime Supporter
May 10, 2010
6,711
SW Louisiana
Re: Just bought a house with a pool-Black Algae and No Chlor

Welcome, it looks like you have a couple of problems the most serious one is too much CYA most likely thanks to those trichlor pucks. To put it simply, the pucks add chlorine and CYA, chlorine gets used up CYA does not, a little CYA is good, too much is bad. At your levels of CYA it is buffering the active chlorine too much which lets algae start growing, once it is growing it consumes all available chlorine. The solution is likely to drain about half your water and replace it then stop using the pucks (or any type of stabilized chlorine), and switch to liquid chlorine / bleach for chlorination, first at shock levels until the algae is dead, then and a lower maintenance dose level to maintain the correct amount of FC.

Ike

ps. your CH looks high too, this may be fixed by the partial drain depending on the CH levels in your fill water (you may want to do the CH test on your tap water to see what you will be working with)
 

linen

TFP Expert
LifeTime Supporter
Jul 30, 2010
8,649
Twin Cities, MN
Re: Just bought a house with a pool-Black Algae and No Chlor

Welcome to tfp, gruve :wave:

Nice job on studying up in pool school and getting the best tool (the test kit) :cheers:

As Isaac-1 said, cya of 75 is pretty high. I am sure you have found poolcalculator.com by now? It says for 75 ppm cya, you need a minimum of 6 ppm FC in your pool at all times to prevent algae from taking over. Obviously, your pool does not have anywhere close to that.

Since you are having algae problems, your pool needs to go through the shocking process.

Take a look at this as well:http://www.troublefreepool.com/turning-your-green-swamp-back-into-a-sparkling-oasis-t4147.html

Reading your post I get the impression that you are fed up with the pool service and that you are very capable. I would guess that the pool service will not "change their ways" so you may want to consider changing them. We are always here to help.

Let us know if you have any questions.
 

BigIslandPoolService

LifeTime Supporter
Aug 14, 2011
61
Re: Just bought a house with a pool-Black Algae and No Chlor

Aloha & welcome Gruve! :wave:

The gang gave you good advice...here is the only one I think they missed (simply because they were concentrating on the more important things first):

If you have high Calcium content in your water, you need to use a smaller sample of water to do your Calcium Hardness test. Use a 10 ml sample, and then each drop of the reagent will be worth 25 ppm--when you do it this way (once a month is enough--calcium doesn't change very fast), you will only use 26 drops instead of 65 drops! Good savings! :mrgreen:

Aloha!
 

Bama Rambler

Mod Squad
TFP Expert
Bronze Supporter
LifeTime Supporter
Jun 22, 2009
23,625
SouthWest Alabama
Re: Just bought a house with a pool-Black Algae and No Chlor

Test your fill water and see what the CH is in it. If it's not very high you'll do yourself a favor by replacing some of the water. That way you'll be reducing both the CH and the CYA. That will make the shock Process much easier.
 

gruve

Member
May 30, 2012
18
Deep South Texas
Re: Just bought a house with a pool-Black Algae and No Chlor

Wow! Hey guys thanks for the warm welcome and quick responses. I'm about to read up on this, but if anyone's around for a quick response, is there a way to lower CYA without draining?

@linen, yeah I sure am pretty fed up... it just seems like they're doing a careless job and then when things become obvious, like color changes, they correct it after the fact rather than seeing those things coming and PREVENTING them.

I have a theory that all the chemicals they threw into the pool over the first few months caused my plaster to start flaking... but again, I'm uninformed, so I don't want to make any assumptions. thoughts?

Our water down here is very hard, so I will test it to see what the CH is. If the source has high CH then what?

Oh and I'm still wondering about the bleach pH ... doesn't bleach raise the pH of the pool?

Anyway, thanks again everyone!
 

linen

TFP Expert
LifeTime Supporter
Jul 30, 2010
8,649
Twin Cities, MN
Re: Just bought a house with a pool-Black Algae and No Chlor

gruve said:
Wow! Hey guys thanks for the warm welcome and quick responses. I'm about to read up on this, but if anyone's around for a quick response, is there a way to lower CYA without draining?
Unfortunatly no, drain/refill or Reverse Osmosis.

gruve said:
I have a theory that all the chemicals they threw into the pool over the first few months caused my plaster to start flaking... but again, I'm uninformed, so I don't want to make any assumptions. thoughts?
I am not sure on this question, hopefully someone will chime in :whip:

gruve said:
Our water down here is very hard, so I will test it to see what the CH is. If the source has high CH then what?
Then you will need to keep TA and ph a little lower. The numbers in your first post (other than CH) were pretty good (especially TA).

gruve said:
Oh and I'm still wondering about the bleach pH ... doesn't bleach raise the pH of the pool?
In practice you can consider bleach ph neutral. It does raise the ph temporarily when first put in the pool, but then when the chlorine gets used up the ph returns almost exactly where it started. My understanding is their might be a miniscule net ph rise, but it is basically too small to measure.
 

gruve

Member
May 30, 2012
18
Deep South Texas
Re: Just bought a house with a pool-Black Algae and No Chlor

Hey thanks for the quick answer... I actually just came across that same info on the CYA question... looks like I'm going to have to drain.

SO

How does one do a partial drain. I didnt actually see the info in the pool school area. The options that come to my uninformed mind are some sort of sump pump, some sort of siphon, or perhaps there's a way to use my pool equipment to do this - like a REALLY long backwash?
 

SPKNout4CHRIST

Well-known member
Mar 4, 2011
262
Goldsboro, NC
Re: Just bought a house with a pool-Black Algae and No Chlor

gruve said:
Hey thanks for the quick answer... I actually just came across that same info on the CYA question... looks like I'm going to have to drain.

SO

How does one do a partial drain. I didnt actually see the info in the pool school area. The options that come to my uninformed mind are some sort of sump pump, some sort of siphon, or perhaps there's a way to use my pool equipment to do this - like a REALLY long backwash?
Do you have a multi-port valve on your equipment pad? It will be a handle that can be rotated to different options (i.e. Backwash, Filter, Recirculate, Waste). If you do have that and see the option for waste I would say that is the first option. If you could post a picture of your equipment pad we could help determine if you have that option and where the waste line is, if there is one.
 

gruve

Member
May 30, 2012
18
Deep South Texas
Re: Just bought a house with a pool-Black Algae and No Chlor

OK i think i can handle that. I'll see if i can get it done during lunch.

Just out of curiosity, does anyone use a "pool app" like to enter in your measurements, track changes, compare results over time, etc. Seems like that would be pretty handy... I shoved a pen and note card in my kit for now.
 

linen

TFP Expert
LifeTime Supporter
Jul 30, 2010
8,649
Twin Cities, MN
Re: Just bought a house with a pool-Black Algae and No Chlor

For apple drones the poolcalculator is also and app.

For android, there is an app called simplepool
 

gruve

Member
May 30, 2012
18
Deep South Texas
Re: Just bought a house with a pool-Black Algae and No Chlor

yeah android here... ill take a look at simple pool...

Just out of curiosity is there a 'safety guide' to know what levels of what chemicals are safe for swimming and not safe...

With all the reading im doing and learning the ingredients of things like algecides and other treatments... is there any concern for chemical exposure? in children especially. I mean, could a pool really be a toxic soup? Some things burn off like chlorine, but others it seems stay in the pool until its drained.

On a side note, I just spoke to the pool guy on my way home for lunch. I asked about the algae and water chemistry... his response was "well the biggest thing is I alway have to brush. As long as I brush, I'll keep it contained." But, in the back of my mind, I'm thinking WHY do you ALWAYS have to brush ... if algae didn't like growing in my pool, say because it has chlorine... wouldn't the brushing be less important?
 

duraleigh

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Mod Squad
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In The Industry
Apr 1, 2007
32,844
Sebring, Florida
Re: Just bought a house with a pool-Black Algae and No Chlor

if algae didn't like growing in my pool, say because it has chlorine... wouldn't the brushing be less important?
Ya' think? :mrgreen: :mrgreen:
 

Isaac-1

TFP Expert
LifeTime Supporter
May 10, 2010
6,711
SW Louisiana
Re: Just bought a house with a pool-Black Algae and No Chlor

Ok, back to the point at hand, your CYA level is well on the high side for a manually chlorinated pool, although not nearly as bad a some peoples, you also live in south Texas in the heart of the sunbelt, so under normal conditions you would want to keep your CYA a bit higher than most people. A target level of around 45-50 for your CYA would be reasonable, given the error range of the test, I would suggest starting with a 30% water drain and replacement, hopefully this would put you around the 50 ppm ballpark. As to how to drain it depends on what you have at your disposal, the pool pump is an option if you have a waste drain line, and a bottom of pool drain that can be isolated from your skimmer, if your pad is set up so your always pulling water from the skimmer then your pump will loose prime as soon as the water level drops below the level of the skimmer (sometimes plugging in a vacuum to the skimmer will work around this, but if it comes unplugged your out of luck)

Ike
 

RobbieH

TFP Expert
LifeTime Supporter
Aug 30, 2010
4,052
Dallas, TX
Re: Just bought a house with a pool-Black Algae and No Chlor

Regarding your plaster flaking, can you post some pictures? I wonder if you are seeing scaling instead of plaster flaking, pictures should help.
 

gruve

Member
May 30, 2012
18
Deep South Texas
Re: Just bought a house with a pool-Black Algae and No Chlor

Alright... first time posting photos so here goes nothin'




These spots showed up this week



Easiest to see the plaster flaking off at the stairs... but there are lots of spots like this across the pool floor



Water is a little cloudy today after the pool guy left... also there's a dark gray 'hole' down at the bottom that i have yet to investigate... but its been there a long time



is that metal staining below the light?



heres my pump... only about 6 months old... was replaced under home warranty



so is this 1.5, 1.25, or 1.85?



started to look into what was being dumped into my pool...



trichlor pucks



i have 2 timers... but no polaris



here's the top of the main valve



I'm guessing i can drain the pool by turning it to waste?



My new filter also got with home warranty



Pro grid DE filter
 

msgtdan

Well-known member
Jul 8, 2011
653
SW MO
Re: Just bought a house with a pool-Black Algae and No Chlor

Algae can get a coating on it that will protect it from the chlorine, that's why you have to brush once you have algae.

To drain, pump to waste on your multiport valve, there should also be a valve to pull all the water from the bottom drain. That valve may be at your pad or a diverter in the skimmer.
 

march2012

LifeTime Supporter
Jan 21, 2012
369
Re: Just bought a house with a pool-Black Algae and No Chlor

gruve said:
OK i think i can handle that. I'll see if i can get it done during lunch.

Just out of curiosity, does anyone use a "pool app" like to enter in your measurements, track changes, compare results over time, etc. Seems like that would be pretty handy... I shoved a pen and note card in my kit for now.
I use a google doc spreadsheet to track mine
 

gruve

Member
May 30, 2012
18
Deep South Texas
Re: Just bought a house with a pool-Black Algae and No Chlor

Well I took a dip over the weekend. The gray spot on the very bottom is definitely a patch of what looks to be concrete underneath the plaster.

Also, there sure was a LOT of debris floating around suspended in the water... little leaves or pollen or other unidentifiable pool junk. Does this mean my filter is dirty or that the skimmers arent working properly?

Is there a way to repair all the plaster flaking or is that going to need a replaster?
 

Spiccolli

LifeTime Supporter
May 23, 2012
65
Gold Canyon, AZ
Re: Just bought a house with a pool-Black Algae and No Chlor

Just out of curiosity, does anyone use a "pool app" like to enter in your measurements, track changes, compare results over time, etc. Seems like that would be pretty handy...
I use https://play.google.com/store/apps/details?id=com.plb.pool.

works great - just set up your pool first in settings, put in your numbers and goals, and it tells you what to do. also keeps track of all your entries.