Algae, any chance I'll have this clear by Sunday Aug 23?

[bauerdr]

We have a 15000 gallon fiberglass salt water pool with cartridge filter- we've never had any issues but last week we had tile work done and the water had to be lowered and the pump was off for 2 days. In retrospect perhaps we should have treated the water for this interruption in filtering. On top of that our filter was in need of replacement. We've had pressure issues all summer and have been cleaning it alot.

Fast forward to yesterday and we return from out of town to find it green with algae growing on the walls and ledges. It's cloudy enough I can't see to the deep end. We start filling the pool to run the filter and also at this time we replaced our cartridge in our filter. Our pressures were down to the start. I vacuumed and brushed the sides. Up until this point we had been using test strips and have had nothing but crystal clear water (2nd season with the pool). I keep stabilizer in a sock in the skimmer and I occasionally have to get ph down. It gets minimal to moderate use.

I tested it with a strip -
Ph 7.2
FC 0
cya not in OK range but not 0

So I had a bag of shock left from original install of pool and put that in. I went to the pool store to get a better test kit and am now using a taylor DPD test kit. They didn't have DPD powder or reagent but were getting it in today.

Last evening I tested the pool using the drops and the FC was 3-6 and the CYA was ~20 (at 30 I could still see the dot but a little above that the dot disappeared)

I added 187oz of liquid bleach according to the pool calculator. I brushed the sides and walls again and the filter has been on 24 hours as of this morning- I woke up to new algae on the walls and ledges and still cloudy but slightly less cloudy.

I picked up the dpd powder and reagent at the pool store this morning and tested the FC and it was 14.4. My CYA still probably 10-20. I just brushed and vacuumed again, cleaned the cartridge- which again was brand new yesterday but had some green algae on it.

I'm planning to keep testing the FC throughout the day- am I on the right track?

We have a party planned Sunday- is there any chance I will have this in check and the chlorine level will decrease to safe swim levels by then?

Here are some current photos- I am able to see my bottom drains in the deep end but the water is still cloudy with a slightly green tint

 

[Texas Splash]

Your water is not the worse we've seen, and you have the potential to make great strides if you follow the Pool School - SLAM - Shock Level And Maintain page to the letter. A couple things to emphasize:
- Do not put any "bags-o-shock" in the water, or use anything other than regular liquid bleach.
- Continue to sweep/scrub, and clean that filter; pump running 24/7 during the SLAM
- So you do have an FAS-DPD (R-0870 powder & R-0871 drops) to test FC? That's very good. Can't SLAM without it.

Simply continue to maintain the appropriate SLAM/Shock FC level based on your CYA per the Pool School - Chlorine / CYA Chart and it will work. The more vigilant and consistent you are with the cleaning and chlorine, the faster you will see results. Good luck!

 

[bauerdr]

Thank you for the reply!

Yes- no more bags o shock! Only using regular liquid bleach.

I will keep scrubbing and will vacuum again this afternoon.

Yes, I have the FAS-DPD R 0870 powder and R 0871 drops. I'm hoping they have more drops as I had to use 72 to get it clear earlier.

Is testing every 2 hours OK or should I do more since my CYA is so low? And is my low CYA worrisome to realistically get ahead of this or in theory will I just go through a lot more bleach?

Thank you!

 

[otter86753]

I just completed a SLAM and until I felt I was at the end, I used a 5ml sample and counted each drop as 1PPM FC. It is not completely accurate for an OCLT criteria of completing a SLAM, but it does save reagent at the beginning of a SLAM.

 

[borjis]

You might just make it for the party. You will use less bleach for the slam with the CYA low...this is a good thing, for now.

Make sure the slam level never goes below what it needs to be and keep the pump running 24/7.

Brush twice a day morning/evening if you can until thursday evening. The water should be
completely cleared by sunday. (though maybe not completed slam)

as long as the chlorine level is at or just below slam level on sunday should be ok for swimmers.

 

[bauerdr]

Thank you- I am thinking I may have it kicked by Sunday but not sure my chlorine will return to safe swim levels.

So at 10 am today I tested and FC was 14.4
I just tested again 2 hours later and my FC is still 14.4- no change??

This should be considered good, yes? But is it possible with a low CYA and visible algae this morning before I brushed and vacuumed, this it has not dropped? The sun is blazing hot today too.

- - - Updated - - -

I just completed a SLAM and until I felt I was at the end, I used a 5ml sample and counted each drop as 1PPM FC. It is not completely accurate for an OCLT criteria of completing a SLAM, but it does save reagent at the beginning of a SLAM.

Ahhh, OK- maybe I will try that next time as I just used 72 drops again.

 

[Crackerjack4u]

Bauerdr Welcome to TFP,

Beautiful pool by the way.

OK this question is for the members that know a lot more than I do about this stuff. I'm still rather new, and don't want to advice you wrong.

Wouldn't adding stabilizer Now be advisable to increase that low CYA level in order to allow the FC to hold better?

 

[Megsyperk]

I wouldn't touch CYA until algae is gone and OCLT is passed.


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[bauerdr]

Yes, didn't plan on doing anything with the CYA right now other than keep my FC level at recommended range. FC holding doesn't currently seem to be my problem. I am just curious as to how the FC hasn't dropped in 2 hours of direct sunlight (pool gets sun from sun up to sun down) with low CYA levels and history of visible algae this morning.

I am confident I'm testing correctly with the dpd powder and reagent.

 

[duraleigh]

I'm hoping they have more drops as I had to use 72 to get it clear earlier.

You were dangerously over chlorinated if your pool is 0 CYA and your FC was 36 ppm.

Going forward, read "The ABC's of Pool Water Chemistry" up in Pool School. that'll help you and at the least buy enough CYA to get to 40 ppm but don't put it in just yet.

You should also be reading the SLAM article and following that to a tee.

With 0 CYA your FC should not be over 10-12ppm. Done is done and I hope there is no damage to your liner. The good news is the FC will drop into the range of 10-12 rather quickly......your single mission should be to test and make sure you keep it there.

You may be going too fast and should slow down a little and learn a bit more about what we teach. Your Filter issue was an issue with your water chemistry....not your filter.

 

[bauerdr]

You were dangerously over chlorinated if your pool is 0 CYA and your FC was 36 ppm.

Going forward, read "The ABC's of Pool Water Chemistry" up in Pool School. that'll help you and at the least buy enough CYA to get to 40 ppm but don't put it in just yet.

You should also be reading the SLAM article and following that to a tee.

With 0 CYA your FC should not be over 10-12ppm. Done is done and I hope there is no damage to your liner. The good news is the FC will drop into the range of 10-12 rather quickly......your single mission should be to test and make sure you keep it there.

You may be going too fast and should slow down a little and learn a bit more about what we teach. Your Filter issue was an issue with your water chemistry....not your filter.

No you misread my original comment. I did not have the dpd powder or reagent last night and tested with the drops and my FC tested in the 3 to 6 range- not 36. My CYA is somewhere around 20- it's not quite cloudy enough at 30 to cloud over the dot but a bit over that the dot does disappear.

My current FC is 14.4 with a CYA of 20. I don't have a liner, I have a fiberglass pool. And our previous filter seemed to get clogged and perform poorly after a guy sprayed sealer on our concrete and it coated the surface of the water- our water has always been crystal clear and tested (albeit with strips) good.

 

[Texas Splash]

With a CYA of 20 and SLAM/Shock level of 10, you should be fine. No need to go much higher though. 10-12 would be optimal so you don't waste bleach.

 

[bauerdr]

And in regards to 72 drops- I had the tube filled to 25mls and added 72 drops which calculates to a FC of 14.4 correct? 72 x0.2 = 14.4

 

[bauerdr]

2 hrs later and the FC is 13, dropping from 14.4.

It seems I'm holding FC fairly well but I just brushed again and thought I saw some green dust on the one ledge. It was hard to see as I have the jets making ripples where I thought I saw it. Just tested my CYA again and it's around 20. So my FC is slightly high in relation to my CYA but I should have it shocked pretty well, does it make sense that I saw some new evidence of algae? I also think it looks cloudier than it did earlier today in my photos.

- - - Updated - - -

One more question- in order to accurately perform the OCLT- I have to turn off our SWG 30 mins prior to testing and do I keep it off overnight?

 

[Megsyperk]

And in regards to 72 drops- I had the tube filled to 25mls and added 72 drops which calculates to a FC of 14.4 correct? 72 x0.2 = 14.4

I would use a 10 ml water sample so you don't need as many drops. You're going to be doing this a lot over the course of the SLAM. I'd preserve reagents if I were you. With 10 ml, each drop is .5.

I performed my SLAM with 10 ml samples; in fact, I've never done a 25 ml sample for FC. :/


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[Texas Splash]

With my FAS-DPD I fill the vile up to the 10ml mark, add my scoop of powder, then count the drops. I then multiply those total number of drops by .5. So 20 drops would give me an FC of 10. There are other ways to do it (as noted above) when someone is simply trying to save on their R-0871 drops. It may not be as accurate, but it helps in a pinch.

Yes, for the OLCT, turn off the SWG.

 

[bauerdr]

I performed my SLAM with 10 ml samples; in fact, I've never done a 25 ml sample for FC. :/


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Thank you! Yes, with my last test (where I got 13) I filled to the 10ml mark and used 26 drops. I'll continue to test that way.

Texas Splash- Thank you re: OCLT and SWG!

 

[Texas Splash]

To follow-up on your 72-drop question:

There isn't normally any reason to do this, but if you need more precision you can do this test with a 25 ml sample of pool water and multiply the number of drops by 0.2. In most situations the added precision is useless and simply wastes reagent.

Again, most will use the 10ml sample though.

 

[borjis]

I know pure accuracy is nice, but never could figure why anyone would want to waste reagent drops with the 25 ml test.

Heck even the TF-100 test instructions indicate the 10 ml test procedure.

What Texas Splash said (off with the swg til the slam is done) plus having it on will skew your chlorine loss test results.

 

[PAGirl]

Most of the time, it is recommended to leave your SWG off during the entire SLAM. It helps prolong its life.