No Chlorine. . . If not Algae, then What?

We filled our pool with water from the tap this week, due to having a new vinyl liner put in. We have a very high iron content in our water so we used water that runs through a whole house filter. I think we overwhelmed the filter - it couldn't keep up with that volume of water running continuously. So, the water was looking green by time the pool was 1/4 full and quite green but clear when full. We put in a gallon of sequestering agent and expected to vacuum (to waste) the drop-out off the bottom of the pool. However, the next morning when I vacuumed, there was nothing coming off the bottom of the pool and the water was still clear and green. By the next day the water had turned completely cloudy green. The TA is very high and we are working on bringing that down...have two makeshift fountains going at the return jets. I assumed the high TA was the reason for the cloudiness. Last night I shocked the pool and this morning I have no chlorine reading. So, now I'm wondering what's going on...we can't have an algae growth, since we just filled the pool, can we? So then, where's the chlorine going? What am I missing here? My numbers this morning are:

CL - 0
PH - 7.4
TA - 460
CYA - 35

Last evening, after aerating for a few hours, there was a light, white "scum" collecting on the top of the pool. We've had something similar to that in past years when we had a large amount of dead algae floating on the top of the pool before it got filtered out. Last night, this looked like collected air bubbles from the aeration, but now I'm wondering if it's not that??

Thanks for any help!

First of all, when you add the metal sequestrant, it does not cause the metals to drop out of the water where you can vacuum them up. The purpose of the sequestrant is to keep the metals suspended in the water to keep them from staining your pool. Is it possible that you didn't add enough for your size pool? Have you tried adding a little more to see if the green starts to change?

Second, in two days in this heat, it is entirely possible for algae to start growing. If so, this may be why you have no chlorine residual--either the algae itself consumed it, or the algae + the metals sequestrant consumed it. It's going to take getting your chlorine up there and keeping it there to clear it up.

I also have two questions for you--what type of test kit are you you using to test with, and did you add CYA to the pool to get your 35 reading? If so, did you add it via pucks (which would cause the metals to fall out if there was not enough sequestrant), or powder (which might cause slight clouding if you broadcasted it instead of adding it through the skimmer)?

Finally, in order to lower that TA, aeration alone won't do it. You need to use acid to drop the pH (and the alk goes down with it), then aerate to bring the pH back up.....then drop it again with acid and aerate until the TA ratchets down to where you want it.

Hope this helps....
Janet

Hi Janet,

Thank you so much for your reply. I was confused about the sequestrant - the guy that installed the liner said it would drop out and then we should vacuum to waste. I've added one gallon so far. I will check the label again and add more, if needed. I added CYA powder via a mesh bag, hung in the skimmer basket. It took about 30 hours for it to dissolve. I am using Ben's test kit that I got last summer.

I have been using Muriatic Acid to drop the PH, then aerating until the PH rises again. I've not been at it long enough to do the cycle more than once yet, but have lowered the TA from 560, where I started, to 460 this morning. I read everything I could find about it on the pool solutions site and on this forum and learned that this is the only way to get the high TA down.

Well, I guess I do have algae growing already then. It took over three days to fill the pool, via our hose, and I didn't have chlorine in there during that time. I guess that was a mistake. So, I'm back to fighting algae. Unfortunately, that's a problem I'm familiar with! :( I'll get it up to shock level again and keep it there, along with a little more Stain Ban, and see if we can't get this water cleared up soon.

Thank you so much for your help, Janet. I really do appreciate it.

The water going from clear green to cloudy green is the real clue to algae. I suggest you abandon all other "corrections" and shock that water up to the shock level of 15 and keep it there. All your other problems are minor once you have an algae infestation.

That's IMHO.

Yes, you should sanitize the pool first before you deal with the metals - the chlorine will get used up with the sequestering agent too. Sometimes sequestering agent makes the water cloudy too, so it is best to know that the water is clean before starting with the metals, this way there is no question that it is not algae. Keep us informed and we can help you through this:)

Ok, I shocked the pool at sundown tonight. I did not add more sequestering agent because I had put in more than the instructions called for already, which could be part of my problem, I now realize. The pool liner guy said I needed to get that sequestering agent in right away because we have so much iron. What I should have done was get chlorine in right away, as the pool was filling, it seems. I must learn not to listen to "pool guys"! :D I'll keep it at shock level now until things clear up. I'll keep you posted and thanks again for all the great help.

The pool guy was correct in saying to get the sequesterant in right away. The purpose of that was to 'deactive' the metals so they would not react witht the chlorine that you should have put in next!

Thank you for the further explanation Evan. I learn more about this pool every summer. By the way, when I said I need to not listen to "pool guys", I was NOT talking about You! :D

Last night, it turns out, that my husband and I both added chlorine to the pool which resulted in shocking it to 26! :eek: This morning the pool looks basicly the same except that when I got down to get my water sample, I could see a little further down the side. My chlorine reading this morning is:
FC - 12
CC - 1
TC - 13

Quote:

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Originally Posted by Pamsel

Thank you for the further explanation Evan. I learn more about this pool every summer. By the way, when I said I need to not listen to "pool guys", I was NOT talking about You! :D

Last night, it turns out, that my husband and I both added chlorine to the pool which resulted in shocking it to 26! :eek: This morning the pool looks basicly the same except that when I got down to get my water sample, I could see a little further down the side. My chlorine reading this morning is:
FC - 12
CC - 1
TC - 13

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OK!!!!! That means you are fighting it and making progress. You should have immediately added bleach to raise the FC back to either shock level or 25, whichever is higher (because you are fighting so much). Check it 2 to 3x a day and add bleach whenever it drops below the shock level.

Keep that filter going 24/7 and vacuum to waste everyday--and brush it once a day too.

Thanks, Carl. We're on it! :) I'll let you know when it's clear and sparkling!