Weird water test results...

[moze229]

I have this algae that's starting to grow, and my water results don't make a whole lot of sense to me. This is likely due to my ignorance more than anything else, and I'll say up front that I do not have a complete test kit. That is being remedied as I type this.

FC : 7 (I try and shoot for 6, since the pool calculator recommends between 4-8) I use chlorine bleach 6% as an additive.
CC : 0
TC : 7
CYA : 50 ( I overshot on the addition of CYA this year, but since the recommended levels are between 30 and 50, I didn't sweat it too much. Last year I had it right at 30)
Temp : 72 degrees. Went up to 75 last week.
pH : 6.3

What in the heck? How did my water get so acidic? I'm going to be adding baking soda today, and I will have a total alkalinity test shortly. Not that it makes a whole lot of difference, but the tap water out of my hose reads pH at 7.4. I've added water a few times this year. I've also had a drain a couple of times. We don't have acid rain here that I know of. And hypochlorite is basic not acidic - and the levels are, and have been within the desired ranges. Not sure where the pool full of battery acid came from. This is my fault because I haven't been testing for anything but CYA, FC, and CC. Never thought a whole lot about my pool water getting that low of a pH.

Back to the algae - how is it growing? The reason this is weird for me is that most of the threads I read involve algae being in the water AND on the walls, floor, etc. The algae I have is only on the bottom in a few spots around the edges. The water is crystal clear and has been all this season. You can scrub it off and it's right back the next day. It's not getting any worse, but it's not getting any better.

Any information to help me out here would be appreciated. As I said, I'm going to be up a TA test kit now along with a lot of baking soda.

 

[JohnT]

What test kit are you using to measure pH at 6.3?

 

[moze229]

What test kit are you using to measure pH at 6.3?

Three. Test strips, and a pH digital Pinpoint probe. Just for fun, I pulled one of my aquarium test kits and got the same result.

EDIT : Just to add, I then when and took those same three tests on both of my aquariums and got the expected results. I am fairly certain that the test results are accurate at least within .2.

 

[moze229]

Started some makeshift aeration for the moment. Took a piece of left over flexible hose that I didn't use and got it connected to the return. Took that and strapped it down to the deck with the water spilling back into the pool. (I sat a rock on top of the hose so that I don't accidentally drain the pool. Not gonna do much but better than nothing. Until I get the TA test I won't really know what to add. The way that my pool is set up there is really not much water movement most of the time because we aren't swimming a whole lot yet. Probably going to have to add some sort of water feature.

 

[ROB N]

You mention you use bleach as an additive... How do you chlorinate, if you use trichlor or tabs they will lower your ph...

 

[moze229]

You mention you use bleach as an additive... How do you chlorinate, if you use trichlor or tabs they will lower your ph...

My ignorance again. Sorry.

I use bleach to chlorinate. I have never used anything else.

 

[moze229]

Man, I didn't think that I'd be able to stump the people on here. It must have been the digital probe that threw everyone off.

Anyhoo, check this out.

TA : 30 ppm

lol

So, needless to say, I need some baking soda. And lo and behold, I bought a big ol' container at Walmart. According to the calculator, I need to add 143 oz by weight to get my level to 70 ppm. Since the water already has a pH of cola, I'm not going to worry too much about the pH change. The result should be favorable in this case. So, I'll add about half and test again tomorrow and see where I'm at. Thanks all!

 

[jblizzle]

How long ago did you add the CYA and how much? That will also lower pH.

Also read this: Recommended Pool Chemicals
Baking soda does not raise pH much if that is why you were adding it.

EDIT: I see it is for raising TA ... you should really get that pH very soon with either Borax or soda ash

 

[moze229]

Thanks jblizzle,

The CYA was added back at the beginning of April. I opened the pool up early this year because of the extremely early warming temps and was worried about algae forming. So I went ahead and opened then.

As far as pH - I'm trying to fight one battle at a time here. I used baking soda to raise TA because it has the added benefit of raising pH. Whether or not it will take me where I want to go remains to be seen. I'll fight that battle next. Then try and figure out the algae.

I also wanted to add that algae seems to be taking the strongest hold in the areas of the pool that get the least sun - hence the areas around the edges and bottom on one side. (The side that's shaded the most towards the woods.) I suppose I'll have to just shock the pool in the end, but I was waiting to see what everyone else thought. I haven't heard any suggestions on the algae yet and I understand why. It really doesn't make a whole lot of sense. So far I've gotten some suggestions for pH. I'll try the algae forum for algae suggestions.

 

[jblizzle]

That amount of baking soda will raise pH by 0.1. You need borax of soda ash for the pH.

Well the #1 priority was getting your pH in line ... then you can start the shock process to get rid of the algae.

Read pool-school/mustard_algae
By your description sounds like it could be mustard algae.

Keep all you posts together.

 

[moze229]

Thanks for the links Jason. I'll take a look.

While I also think it's best to keep posts together, the algae portion of my post doesn't apply to "Testing and Balancing Your Water" directly. While water imbalances tend to cause algae to take hold to begin with, I may get better results on the correct applicable forum. You are the only one that has mentioned one thing about it so far anyway. Perhaps I should have just left that part out of my original post.

Thanks again for the links!

 

[jblizzle]

Most of us regulars only look at the Active Topics and pay no attention to what forum the post is actually in ... at least that is what I do.

 

[Bama Rambler]

^^ That's what I do too. And if I see a post that has had several replys I'll just scan over it and come back to it later if it appears the OP is still having a problem.

Your immediate problems were pH and TA. Once you get those fixed post back about the algae and we'll attack that.

One of the first things you stated was that you don't have a good test kit and without that you can't run the OCLT, so there was no reason delving into that until you got the new kit. Which you stated you were getting.

 

[moze229]

One of the first things you stated was that you don't have a good test kit and without that you can't run the OCLT, so there was no reason delving into that until you got the new kit. Which you stated you were getting.

Hey Bama,

Actually, I have an awesome test kit according to TFP. I bought TFTest products. I just didn't buy a complete test kit. I bought the CYA and FAS-DPD tests. I have other ways of testing for pH and alkalinity. My fault there wasn't actually buying a test method (since I already have them), but rather not testing for them. As far as the OCLT, from what I understand this tells me whether or not something is living in my water. Since I already know that I have some type of algae living in my water, performing this test seems moot until the shock/algae clean-up process is viewed as possibly complete. Additionally as you will see below, my loss of FC in ~24 hours is .5. This is also a bit confusing since I know that I have something living in the pool. While it's not the "official" OCLT test, it is an approximate 24 hour viewpoint of FC loss.

After adding about 8lbs. of baking soda... my

TA : 60ppm
pH : ~6.5 (as jblizzle predicted)
FC : 6.5
CC : 0
TC : 6.5
CYA : 50
Temp : 71 degrees

I need to add a little more baking soda to get TA up to a minimum of 70. I'm also now off to buy Borax I suppose. Since my TA is still low, whatever alkalinity the Borax might add will be utilized in the TA rise process. Or perhaps I should use the soda ash "pH up" stuff instead since my pH is so low. I tend to prefer using one thing to control each factor if at all possible.

 

[Bama Rambler]

Get that pH on up and then lets deal with whatever you suspect is in the water.

You are correct about the OCLT being after you think it's all cleaned up. In your case you may want to run it to verify if it's algae you're seeing or something else.

 

[moze229]

I elected to go with soda ash (pH up) instead of the Borax to eliminate having to test for yet something else (borates). I'm going to be adding some stuff here in the next few minutes and will update with the results. I don't suspect having to wait much more than an hour for the pH test, since soda ash is just as soluble, or even more so than baking soda.

In your case you may want to run it to verify if it's algae you're seeing or something else.

Well, as I said in my last post I sorta did. I didn't do the "just when the sun goes down - just before the sun comes up" part, but the rest of it was the same. In 24 hours, I only lost .5 FC, which tells me (based on just that finding alone) that there is nothing living in the water. I know this not to be true, unless there is some other non-organic thing that can be existent in pools that comes back in the same exact place after it's removed/cleaned.

 

[Bama Rambler]

Dirt tends to recollect in the same place each time due to circulation paths and/or irregularities in the pool.

 

[moze229]

Ok. After adding the pH up, I got a pH reading of 7.4. TA is now at ~65ppm after adding just the soda ash. I didn't want to add more bicarbonate until I saw how much of an increase the carbonate had on the TA. So I'll eventually be adding a bit more baking soda and perhaps a tiny bit more soda ash.

Before I do that though, I need to get to the bottom of the suspected algae/mysterious dirt problem. I've been reading that when shocking the pool, it's best to do this at lower TA and pH levels. So before I fine tune anything, I need to figure out whether or not I need to shock.

What is the first step in attempting to identify this suspected algae? My description earlier is really the best that I can provide. I can try and take some pictures and see how that works out, although I'm not too confident in the results. All that I can do it try. I'll pull one of my telephotos out and see what I can get.

 

[jblizzle]

How does it feel? slimy?

Try the OCLT again ... not sure how it is possible to only loose 0.5ppm FC in 24 hours

 

[moze229]

Yeah. It's algae slimy. :-D

I will do the OCLT today again. When I first sat things up this year, I never did loose more than .5 per day. Of course, the accuracy of that can be questioned, since an explanation to how algae got started in the first place remains a mystery.

Here are some pics that I took just a few minutes ago. Certainly looks like algae to me.

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And I will say that it looks much worse in pictures than it does in person. I purposely left the photos a bit dark to help allow the algae to be seen rather than the reflection of the water. I was too lazy to go get my polarizing filter. Note that there is no algae (At least that I can see - I didn't get out there with a microscope) on anything other than the floor and around the edges. There is none on the wall, ladder, or anything else. The water is also crystal clear as it has been since day one.