Algae!

[Klundell]

Hi, I need so help!! I have been keeping my pool prestine all summer, my number have been great this whole time. I check DAILY, and adjust daily. My CYA is around 50 so i keep chloroine levels around 7. Today I came home from work and my pool is green! I tested chlorine and it was still at 6, and no CC. What in the world am I doing wrong? I know algae is a chemical problem but i have kept it stable! Please help. I’m super bummed about this.

 

[Texas Splash]

So a quick green basically overnight huh? Anything odd in the weather? Too early for monsoon season isn't it? Nothing could've spilled or flowed into the pool while you were away? How about your chlorine? Any chance that got mixed up or the stuff you used had an additive in it? If there was nothing out of the norm, it may just boil-down to a testing error. Weather's getting hotter. What if the CYA is actually higher than you thought, resulting in a higher FC level? That's all that comes to mind. Our pool water can show us signs that something is off, even in our best attempts to keep it clear. Although granted usually it gets a bit hazy first before turning into a green monster.

I suspect you'll just have to put your SLAM hat on and let the chlorine do it's thing. But if you find anything else to be suspicious, let us know.

 

[Klundell]

Thanks Texas. It was unseasably cold and rainy over the weekend. But other than that no weirdness with chemicals. I added DE to the filter. I tests the CYA sat. And it’s between 50 and 60. I always lose 4 ppm daily. And add about 100oz of bleach daily. I guess I’ll just slam - again- then blow my pool up. �� I’m for sure getting a swcg when I’m able.

 

[Texas Splash]

Yes, I'm afraid that daily loss of about 4 ppm is right on the edge of what we like to see. It looks like in your pool (20K), 100 oz is about 3.4ppm of FC. Any chance the DE you added was not for pools? Just curious as that's about the time the water changed as well. There are some food grade DE products that we avoid for pools. Other than that, it sounds like that borderline FC loss caught up with you. Sorry.

 

[zea3]

Anytime your CYA tests between increments of 10, round up. Read yours as 60 for your slam and dose the pool accordingly. Try and keep the FC on the top of the recommended levels and don't let it drop to the minimum after your slam is completed.

 

[frustratedpoolmom]

You sure its not pollen or some kind of iron issue?

 

[Klundell]

Maybe I’m just on the edge of too little chlorine? I keep it at 7 over night and when I come home from work the next day its usually at 3ppm. Do you think the constant dipping to 3 daily would cause it to go green so fast? Which means i need to keep it at 9 so it never drops below 5, right?

The DE is for pools, I checked the box. And its the second time I have used it with no issues the first round.

I live in a kind of farmy neighborhood- weird for PHX right? I have 2 acre horse property right next door that kicks up a ton of dust, and then my back yard backs up to the canal where people and dogs walk all day. We also have chickens, and our yard is irrigated with canal water (which just happened actually the day before the green monster showed up). I know we all disagree with phosphates around here.... but could my situation be that there’s just tons of material floating around the air?? Or is it that I have been adding just a tiny bit too little FC daily?

Hhaahaha man the margin of error on this pool thing is TIGHT!

Thanks for everyone’s help. I shocked up to 30ppm yesterdsay (high but I wanted to be SURE) and this morning it has a lot of white in there, so Ive been brushing this morning and the filter has been running on med since yesterday.

Oh- one last question. I have a variable speed, should i be running it on low, med,or high? My med is 2500, high is 3000 and i think i set the low like at 1500.

 

[Texas Splash]

I live in a kind of farmy neighborhood- weird for PHX right?

I was stationed at Luke for several years, so I totally get it. But you can run the pump on low. Kick it up when vacuuming or just to purge the system of air. The big thing is continual movement and circulation of the chlorine and dead organics back to the filter. All that white you found is a sign it needed some chlorine. Good you caught it now.

 

[mknauss]

You most likely have a higher organic load to deal with than most. Especially with horses next door. That dust includes manure dust. Same issue with dogs. Their fecal matter in our heat dries quickly and the 'dust' blows into the pool.

You need to maintain your FC so that you never go below target and you add each day the amount you lose each day. That may easily be 4 or 5 ppm FC.

 

[zea3]

Yes, try keeping chlorine at 9 for a couple of weeks and see if that helps. All the dust that gets blown around could also be bringing organics in with it that increase your chlorine demand. You can run your pump on low 24/7 and kick it up to vacuum as needed.

 

[Klundell]

Thank you all for the info!! Appreciate it!

 

[Klundell]

I was stationed at Luke for several years, so I totally get it. But you can run the pump on low. Kick it up when vacuuming or just to purge the system of air. The big thing is continual movement and circulation of the chlorine and dead organics back to the filter. All that white you found is a sign it needed some chlorine. Good you caught it now.

You left PHX for TX? Poor choice!! JK

- - - Updated - - -

You most likely have a higher organic load to deal with than most. Especially with horses next door. That dust includes manure dust. Same issue with dogs. Their fecal matter in our heat dries quickly and the 'dust' blows into the pool.

You need to maintain your FC so that you never go below target and you add each day the amount you lose each day. That may easily be 4 or 5 ppm FC.

Yes, we have 2 dogs too... Im pretty sure I understand what I was doing wrong. Looks like I need to up it to a gallon of bleach a day. Seems pricey! Its about 3.22 per gallon here, which means 100 bucks a month. Sound about right to everyone else? Feels pricey!

 

[mknauss]

What strength bleach? But yes, during the summer, you do need to use more chlorine.

That is why a SWCG is so tempting. You pay upfront for the chlorine.

 

[Klundell]

I buy the 10% bleach. And yes, I do see the benefit of the SWCG. I need to start looking into it.

 

[Klundell]

Backwashing question: I read here that you need to BW: Rinse : BW : Rinse. My sand filter has a manual handle that I turn on in order to backwash, then I just turn the pump on high while the water goes out into the yard through a pipe. Once it runs clear I manually push the handle back, and go back to regular filtering. Am I doing this right? What does it mean by backwash, then rinse?
Also, I usually backwash when its 10 psi above starting. I also read somewhere here that it may be better to do it around 20-25% above starting? Right now the pump is 5 psi above starting.

 

[mknauss]

Pool School - Routine Pump/Filter Maintenance

Pool School - Maintenance and Cleaning of Pool Filters

Some good articles to review.

 

[Klundell]

Yes, I'm afraid that daily loss of about 4 ppm is right on the edge of what we like to see. It looks like in your pool (20K), 100 oz is about 3.4ppm of FC. Any chance the DE you added was not for pools? Just curious as that's about the time the water changed as well. There are some food grade DE products that we avoid for pools. Other than that, it sounds like that borderline FC loss caught up with you. Sorry.

Hi! How did you figure out 100 oz was about 3.4 ppm? I ran a test today to see how much chlorine would increase x ppm, using the pool math app to tell me what to add. My app said to add 90 oz in order to increase my ppm by 3.5. After 1 hour of running the pump on high I retested, and my water had increased by only 2 ppm. This makes me think my pool is bigger than 20,000 gallons? Is there a way to figure this out with out measuring, or using the bromide calculation that I read about on here?

Update: added more chlorine...122 oz increased in 3.5 ppm

 

[Texas Splash]

I use PoolMath by starting with a zero to something goal (i.e. 0 to 30). For bleach I update the WEIGHT field to show to % strength, and I make sure the pool gallon size is correct at the top. From there it's just adjusting the TARGET value until I see the dosage amount in the remarks row. Then I can adjust the TARGET valve up or down until I see a match based on the poster's description.

 

[Klundell]

Thanks for your help!! Turns out my pool is closer to 28000 gallons, not 20000. Crazy how much of a difference that makes.