Stuck at cloudy blue after a severe algae bloom - need some pointers!

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T

tseger31

Gold Supporter
Jul 25, 2022
34
Grand Rapids, Michigan
Pool Size
13500
Surface
Vinyl
Chlorine
Liquid Chlorine
All -

Thanks for reading my post. I'm stuck at the cloudy-blue step of ridding my pool of a serious algae bloom. I posted pics below of where I started and where I'm currently at (13,500-gallon pool). Just got back from my local pool store and I've posted my water test results below: (keep in mind CH is high because of shocking the pool, etc) My pool store told me that my pool is "stuck" where it is because my CYA and phosphates are way too high? The high CYA is my own fault...before the algae bloom started a couple weeks ago I was keeping my pool chlorinated with Chlorine Tabs which I've learned is bad because they jack up your CYA! So during the last two weeks, my pool store has had me shocking the Crud outta my pool with liquid chlorine, etc. I was told today that my CYA is so high that it could be causing inaccurate readings of all my other test results? I was told to drain my pool 60% because that's the only way to get my CYA number down and until my CYA goes down nothing else I do to the pool will affect it all that much?! The "green" pic below is from 2 weeks ago. The "cloudy blue" pic is from 2 days ago and the last picture is from 30 minutes ago. I'm assuming all the light-greenish spots on the bottom of my pool are dead algae carcasses since I'm now at cloudy-blue and the green appears to be gone? Since I was told to start draining my pool and seeing how I don't have a sand filter system w/ a "vacuum to waste" option (I have a cartridge filter) I'm going to drop a submersible sump pump down to the bottom and drain the pool with that while using it to vacuum-up all the light-green colored spots on the bottom of the pool (simulating a "vacuum to waste" process). Can someone please tell me if there's a better alternative for clearing up my cloudy-blue that happened because of an algae bloom?

FC: 6.14 ppm (this was 15.1 a week ago as I was shocking the algae)
TC: 6.14 ppm
CC: 0 ppm
pH: 7.6
TA: 165 ppm
CH: 198 ppm
CYA: 135 ppm
Iron: 0 ppm
Cop: .2 ppm
Phos: 3607 ppb


Thanks!
Todd
 

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Hi, welcome to TFP! Your CYA is way too high and your current FC level is too low to prevent algae growth as long as the CYA is that high. You are on the right track to drain and refill the pool. Since the CYA test is only accurate up to 100 ppm your actual CYA may be higher. I would drain about 80% of the water and vacuum out as much dead algae as you can. Once the pool is drained and re-filled we can help you get the water balanced again. I would stick with liquid chlorine since it does not add any CYA to your water. Any chlorine granule or tablet that is labeled dichlor/trichlor... is going to contain CYA. Do you currently have a test kit?
 
zea3 said:
Hi, welcome to TFP! Your CYA is way too high and your current FC level is too low to prevent algae growth as long as the CYA is that high. You are on the right track to drain and refill the pool. Since the CYA test is only accurate up to 100 ppm your actual CYA may be higher. I would drain about 80% of the water and vacuum out as much dead algae as you can. Once the pool is drained and re-filled we can help you get the water balanced again. I would stick with liquid chlorine since it does not add any CYA to your water. Any chlorine granule or tablet that is labeled dichlor/trichlor... is going to contain CYA. Do you currently have a test kit?
Click to expand...
Hi - thanks for responding! Yes, I have the Taylor K-2006C testing kit.
 
zea3 said:
You can run the pool with higher CYA levels, you will just need more chlorine to do so. Have you looked at the FC/CYA Levels?
Click to expand...
Here's my question...I'd rather drain my pool 50% vs. running it with a super high CYA level. But here's my question...and it may be a dumb one, sorry! If I drain my pool 50%, during the 9-10 hours it takes to refill the lost 50%, will the algae bloom take-over again during that time because obviously all my chemical levels will go down during the 50% drain?
 
Hi,
Draining it won't lower your chemical levels, as the concentrations will be the same as you drain, but the re-fill with new water will dilute your levels.

If you lower to 50%, and refill with water that has no CYA, your 135ppm should drop to 67.5ppm, so, still a bit high, but may be reasonable if you get a lot of strong sun. Oh..., looks like you're in Grand Rapids, Michigan.... Yeah, Zea3's suggestion of draining 80% doesn't seem crazy :). That would put you nominally at 27ppm.

You may be tempted to do this in stages (I know I would be!), but you may use more water with that approach, as well as drag it out.

How confident are you in that 135ppm - have you tried to validate that number?

I don't really want to offer any advice, as I'm pretty new to pool ownership and maintenance, so I'll leave the more prescriptive advice to others for now.

Have you got a way to hook your vacuum attachment up to that submersible pump? If not, have you considered pulling the cartridge filter out and disconnecting the return line from the pool? I think that would give you a cheap and nasty 'vacuum to waste.'
 
You can add liquid chlorine in and brush the pool to mix it in before the pool fills back up. You will lose chlorine during the draining process, but once you start refilling you can add liquid chlorine. If you don't have a pool brush you can use your pool net to mix the water a bit. Your submersible pump can help mix the chlorine in too. Just use it to recirculate the water.
 
I'm not to keen about draining my pool even 50% because I just did the math. Filling a 5-gallon bucket w/ my garden hose took 84 seconds. I have a 13,500 gallon pool...if I drain it 50% it'll take 31 hours to re-fill it w/ the garden hose. Even doing it in increments I risk putting unneeded strain on my well.

So the only answer to getting the CYA down is to drain the pool? There's no chemical on the market to lower CYA?
 

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There is some enzyme that alleges they can lower CYA and we have had members who have tried it. Some found it dropped CYA a little and most found it did nothing at all. If you've only got another month or so in your swim season I would drain the pool down 1/4 and refill. Just know you are going to need to keep the chlorine much higher to prevent algae from growing again. When you winterize you will drain down the pool a little more, then in the spring you can look at draining and replacing more.
You might want to look at getting water trucked in at the start of next swim season so you can get rid of all the CYA without blowing up your well. You may also want to consider upgrading to a standard above ground pool pump and filter to make pool maintenance easier.
 
zea3 said:
There is some enzyme that alleges they can lower CYA and we have had members who have tried it. Some found it dropped CYA a little and most found it did nothing at all. If you've only got another month or so in your swim season I would drain the pool down 1/4 and refill. Just know you are going to need to keep the chlorine much higher to prevent algae from growing again. When you winterize you will drain down the pool a little more, then in the spring you can look at draining and replacing more.
You might want to look at getting water trucked in at the start of next swim season so you can get rid of all the CYA without blowing up your well. You may also want to consider upgrading to a standard above ground pool pump and filter to make pool maintenance easier.
Click to expand...
I do have a standard above ground pool pump/filtration system...the one that came with the pool.
 
No worries! I started a new forum thread regarding draining my pool because of my algae issue here:

Question about draining pool

Hello! Just joined this site a couple days ago, just updated my signature and just made a $100 donation to TFP. Thank you for all the pool knowledge and wisdom newbies like me can obtain on a site like this! I'm DONE with going into our local pool stores! Current pool reading from my pool...
www.troublefreepool.com www.troublefreepool.com
 
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