Getting Rid of Baquacil and Heavy Algae in an Indoor Pool

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D

Dsigafus

0
Apr 26, 2008
12
Lenoir North Carolina


Hello everyone, this is my first post and wanted to share what I've gone through getting Baquacil out of my pool and killing off the green alage. This web site has been so helpful and I'm thankful to have it while searching the Internet for help.

My pool is 13,500 gals vinyl with a 1 HP Hayward Superpump and a 244T sand filter and we have been on Baquacil for 1.5 years. I never liked it but my husband got sold on it through the pool company we were dealing with that it was much better to use, especially indoors than chlorine. I never felt the pool was safe to swim in so in reality I haven't used my pool since Baquacil was introduced in it, for the most part because the algae would creep in here and there too often.

I stop putting anything in the pool about a month ago to reduce the levels of Baquacil before starting the converting process. Well, when I did that the algae grew, grew, grew. I would still brush several times a day and backwash often and of course get water tested with my Baquacil test strips and from the pool company. Both testing methods said my Baquacil levels were still really high all through out the month. I decided to take the plunge and went with GLA super shock and doubled it. It started killing the algae right away and the pool turned from an emerald green to a lighter blue green color - no browns, or other strange colors. I could not see the bottom of the pool even in the shallow end. I'd brush anyway towards the main drain. I did not see any goop or strings in the water so I thought well maybe I didn't have as much Baquacil in the water as the tests were stating. I didn't have a test kit at all and after two days nothing was changing - it stayed the same after the first super shock. My pool company guy said to shock again and once again double the amount from what would be normal. I did, and when I did that the water turned brown and a sick yellow -- I was concerned and my pool guy said he didn't understand why it would turn yellow. So, I went to my local pool supply, they tested the water sample and said my CYA levels were 100 with no FC showing, Baquacil was 6ppm, 0 metals. They said I had chlorine block and I would have to drain the pool. That caused me some real concern since I had a vinyl liner. I purchased a Pentair Pro-11 test kit and off I went to drain water. I drained my pool down to 18" all the while keeping the vinyl liner wet to avoid any shrinkage. Refilled the pool (water still looked an ugly brown/yellow) tested the CYA levels which showed at 40 and shocked heavy using the pool calculator I found on this web site. I continued to test all through the day Friday, and Saturday and the the chlorine levels were holding at least 10ppm or greater (test kit only goes to 10ppm). I still could not see the bottom of the pool. However, today (Sunday) I can see the bottom of the pool and can see the main drain a little bit in the deep end. I backwashed and the most awful goldenrod color came out - backwashed 5 mins, rinsed, 5 mins.

The pool water is not yellow anymore and is still very light green, or maybe really a blue green.

My question I have - is this yellow brown coming from the Baquacil? I also notice in the skimmer the water has some deep yellow still and floating junk. Should I shock again or pass on that and wait since the chlorine level is holding at least at 10ppm or greater?

Plus, I was wondering what type of chorine I could use since I really don't want the CYA levels to increase. We had always used the 3" tabs in a inline chlorinator - I now have a new offline chlorinator but I've kept it empty through this conversion process and getting the algae removed. Any input will be helpful, and sorry this was so long, once again thank you.

Debbie
 
Welcome to TFP!

Strange colors are to be expected when converting from baquacil to chlorine.

You really should get a good test kit with a FAS-DPD chlorine test, like the TF Test Kit or Taylor K2006. It is going to be difficult to finish the conversion without it.

The CYA level is going to make the conversion take longer. It sounds like you are well along, but there is more to go. You need to keep the chlorine at high shock level, FC of 25 given the CYA level of 40, until CC goes to zero. Without a better test kit that is going to be tricky. That may yet take quite a bit of chlorine.

Once the CC level goes to zero you have to change the filter media, sand, grids, fingers, or cartridge depending on what kind of filter you have.

Chlorine block (or lock) is a myth that pool stores use when they can't really explain what is going on. In this case the partial drain and refill was a good idea because CYA was so high.

Bleach is a good chlorine source, regular household bleach (unscented or "original scent") from the laundry aisle of the grocery store. In some areas you can get more concentrated bleach, or liquid chlorine, from the pool store for a good price but in other areas the grocery store is your best bet. Depending on your CH level you might also be able to use some cal-hypo, but only for a while or your CH level will get too high.
 
Hi Debbie and welcome to TFP!

Sounds like you are on your way in your conversion.

Do you have an indoor pool?

If you will add all your pool and equipment info in your signature, it will be helpful to those trying to give you advice.

Good luck and glad you are here :)
 
Thank you all for responding and let me say what a difference from earlier today when I posted and looking at the pool at 9pm this evening. No green, and I can see the bottom of the pool (deep end too)clearly and the water is just a little hazy. I'm hoping by tomorrow morning it will be even better.

Jason, I will get a better test kit even though this one does give me 11 different tests. I have already booked to have the sand and filter cleaned. The filter is brand new - I had just upgraded to a larger filter just prior to making the decision to get off this Baquacil junk. As for the FC I'm not sure what level it is at since my test kit only goes to 10. I've added makeup water twice after backwashing and it still reads 10. As for the CC when I do the test for that it also shows 10 and the test kit is this DPD - the little tablets you put in the water sample (DPD #1 for FC, and then add DPD#3 for CC). My PH is reading 7.8, CH 250, Alk - 100. The skimmer is also now clear - no yellow and no floating particles.

Joyce, I will do that - and thank you - it was very scary for me at first doing this and frankly without this web site I'm not sure I would have attempted it. I read everything I could on both the conversion and on getting rid of this terrible case of green algae. Right now I'm very happy on what I see in my pool and tomorrow I know it's going to be better.

Thank you all for the time to put into these issues - especially since the pool company's do not seem to have a clue how to help.

Debbie
 
You can try diluting the water sample with distilled water to read higher chlorine levels. The results will be less accurate but usable up to a point. Try mixing one part pool water with one part distilled water, testing that, and multiplying the result by two, or one part pool water and two parts distilled water and multiplying the result by three.
 
Jason, I'll do that and I will order a better test kit that will give me the higher readings. Hopefully, I won't ever have to go through this again. One thing is good - I've learned so much about pool chemicals, and situations that can and do occur. I intend to keep up on monitoring my pool on a timely basis and I agree that is why I need a really good test kit.

The type of chlorine I will use is something I have to look into - I didn't realize the problems about the CYA for an indoor pool and I really don't want to drain my pool again, at least not that far down.
 
Joyce - I'll have to take some or I may have some in my stash back when we put the pool in. That would not help many for the topic at hand though. Plus, I'll have to study how to post the pictures. I didn't do any through this algae cleanup or conversion process. I guess I should have.
 
This is just an update as of 9 am this morning. Pool water crystal clear. However, I found a few spots of algae around the pool and it looks like there are some stains in a few spots since I can brush and brush and the stain remains.

FC 10, CC 10 - I also backwashed again this morning for 4 min., rinsed for 3 min. and still more deep dark goldenrod came out for a full minute. This must still be the baquacil in the filter or lines.

Do I wait to change the sand and clean the filter until I no longer have any of this goldenrod junk coming out during backwash?
 

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You want to keep up the high chlorine levels and not change the sand until the FC level holds steady overnight. But you need to FAS-DPD test to really determine that. Since the test is coming you might as well wait for that. Also, I would expect CC to have fallen below 10 by the time FC holds overnight, so I don't think you are there yet. The amount of goo you are backwashing out is also a good indicator that you aren't at that point yet.
 
Jason - I haven't added any chlorine for two days and the reading is always the same. I understand that since this test kit I currently have only goes to 10 the FC could be falling and I just don't know it.

I didn't have distilled water but I did have filtered water and I let it sit in a glass overnight and would stir it from time to time since water movement will make vapors rise to expel any unwanted in the filtered water. I did the 1/2 half pool water and 1/2 filtered water and the results came in at 5 so that would mean 10 right? So, if that is true I need to add more shock?

The water is so clear - I see all the little imperfections in my liner ... it's been a long time since I've seen the water like this. Will the stains remain or will the chlorine over time remove them. They aren't real dark but I can certainly tell they are there. (My husband shocked the pool 1.5 yrs ago without testing for metals and we had metals in the water - it stained the liner all over and this is how we got sold on Baquacil. The pool people removed most of the stains and I don't remember these stains remaining but I could be wrong).

I guess I want everything to be perfect ...
 
You can confirm that the filtered water is acceptable by doing a chlorine test on straight filtered water. If FC and CC are both zero then you are fine with the filtered water.

You need FC up at least to 25, possibly higher, because of your CYA level. From your test results it sounds like FC is indeed 10 right now.

The conversion goes in a couple of stages. In the first stage chlorine gets consumed almost instantly as it combines with baquacil and you get all the strange colors. During the second stage the water clears, CC levels get very high, and the reaction slows down significantly as most of the remaining baquacil has gotten gooey and reacts more slowly. During the final stage CC starts to come down significantly and FC holds overnight but there is still some baquacil hiding out here and there. The middle stage can take a while, and is normally done without any CYA. CYA slows everything down further so you may be in the second stage for a while (days to weeks).
 
Jason - that sounds like I need to shock again (I'm using GLB Calcium Hypochlorite 65%, available chlorine 65%). Also, I have the 3 in tablets stablized but I'm not using them right now until this is over - should I be using them along with Cal-Hypo?

The thing that stumps me is the CC is the same as the FC, which would indicate 0, since you subtract the CC from the FC, right? My test kit book says CC should not drop below 0.20ppm difference from FC and if it does would indicate to superchlorinate.
Am I understanding all of this correct?

Also, just for your information - I replaced my filter (upgraded to a larger one) six months ago and put new sand in at that time. I guess with the Baquacil being used even for six months my filter is contaminated, just maybe not as much as if it was a longer period.

The first time I shocked (double dose) the water turned gray,white, and settle to an aqua after a day. The chlorine did just disappear which I was told it was because of the CYA levels. The second time I shocked that when I got all the strange yellow, orange. brown colors. Since the CYA levels have been down the chlorine levels seem to be holding. The third time I really put a lot of shock in (56 ozs).
 
Do not use the tablets, they will raise the CYA level higher, which you do not want right now.

You can continue using cal-hypo as long as your CH level doesn't get too high. I haven't seen you post a CH level, so it is impossible to say if there is an issue there or not.

Total Chlorine (TC) = Free Chlorine (FC) + Combined Chlorine (CC). If you are using the DPD chlorine test, it measures FC and TC and then you calculate CC by using CC = TC - FC. If you have actually been listing TC as CC then you might already be in the third stage but you need to check using the test with dilution, since the normal test will measure TC over 10 as 10.

In normal operation you want to shock when CC is greater than 0.2 or 0.5 (depending on the precision of your test kit).
 
Your right - that is what I meant. I did the test again with the filtered water and it appears to be the color did not darken or lighten when I added the DPD#3 for total chlorine (5). Someone needs to make a digital test unit that's higher than 10 ppm then I wouldn't have to ask myself did that color change.

My CH is 200
 
With the FAS-DPD chlorine test you add drops till the sample changes from pink to clear, which is much simpler than a color comparison.

Your CH is reasonable, so you are good using cal-hypo for the conversion. Eventually CH may get too high if you keep using cal-hypo forever.
 
Jason - I decided to do the 1 part pool water, and 2 parts filtered water using a eyedropper to get exact levels for each. Still registering 5 - so I must be having some difficultly judging color or something using the 1/2 of each (it didn't look to me to be a 10, so I selected 5) however doing the 1 part pool water, and 2 parts filtered it for sure is a 5 which means FC=15, and TC=15, and CC=0, right?
 
When using dilution your results are much less precise than they would be without dilution. From your description FC 15 and CC 0 is as good a guess as any but the results are probably +-5 or worse.

I suggest adding 10 ppm of chlorine, letting things circulate for an hour, and doing the 2 to 1 dilution test again. The chlorine can't hurt and will probably help and it gives you an opportunity to try your testing again knowing that the numbers should have changed.

Wait for the FAS-DPD test before deciding that you are done. From the sound of things you are either done or very close, but wait for the more precise test to be sure. After you are sure that FC holds steady overnight and CC is reasonably low it is time to change the sand. It is too bad that the sand is nearly new, but even so the baquacil will have ruined it and it need to be changed.
 

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