high cya and water restriction

Algae problems in swimming pool water.
Green (cloudy) water or slimy pool walls.
Black algae. Mustard algae. Pink or white pool mold.
carlj0599

high cya and water restriction

Postby carlj0599 » Sun 19 Aug, 2007 21:10

so here's my predicament....

been fitghting mustard algea for two weeks..........water has been green/yellow.........shocking every night using dichlor........recently switched to cal-hypo............after reading all the posts and realizing i was in similar situation to many of you thought why isn't the shock working.........went to pool store and bought better test kit to check cya..........what do you know.......cya is 100+............solution is to drain water and refill to lower cya......... but in SC....we're under water restriction due to lack of rain........so........do i continue to shock to keep algae at bay (i.e. water cloudy, slight green/yellow) and wait until water restriction is lifted since i can't drain 50% of the pool and refill? ...or just let it go until i can drain/refill??..........what a bummer!


chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2382
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

high cya and water restriction

Postby chem geek » Sun 19 Aug, 2007 22:07

If you can't dilute the pool water to reduce the CYA, then you can use an algae killer. The fast but expensive choice is a phosphate remover. Another alternative is a copper-based algaecide, but you'll have copper in your pool that you'll then need to sequester. Probably the phosphate remover is the better choice, though it won't kill existing algae -- it'll just prevent it from growing -- and eventually it will die (from lack of nutrients). At least you can then shock with chlorine to oxidize it.

You can also kill the yellow/mustard algae with chlorine, but since that requires shocking with 60% of the CYA level, that's probably impractical in your case since the CYA is so high, so the phosphate remover may be the best choice until you can drain/refill to lower the CYA.

Just curious, what was the Free Chlorine (FC) you maintained when you got this algae?

Richard
carlj0599

high cya and water restriction

Postby carlj0599 » Mon 20 Aug, 2007 17:32

thanks for the response...

i had been running between .5 - 1 FC with weekly shock and brushing b/c i have a Nature2 filter and the pool store said i should run at about 1 FC (also the reason i was using dichlor)......pool temp has been at 80 or below since opening due to the amount of trees around the pool.....as a first time pool owner i was not prepared for the lack of rain and high temps that we've had over the last three weeks.....hence, i should have gotten the FC up to at least 3 with weekly shock, but i guess all along using dichlor i was raising the CYA...going forward i will use cal-hypo to prevent the cya getting too high when the water temp hits 80+....

this weekend FC was between 9-10....
carlj0599

high cya and water restriction

Postby carlj0599 » Mon 20 Aug, 2007 17:34

i had put PhosFree in the pool twice before the algae invaded.....should i put in a 'shock' equivalent of the PhosFree? I think recommended dosage is 3 capfuls.....i have a 26700 gallon pool.
User avatar
mr_clean
Swimming Pool Superstar
Swimming Pool Superstar
Posts: 398
Joined: Thu 16 Aug, 2007 14:32
Location: So Cal

high cya and water restriction

Postby mr_clean » Mon 20 Aug, 2007 18:06

just a question how many hours a day is pool running?
chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2382
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

high cya and water restriction

Postby chem geek » Mon 20 Aug, 2007 19:02

Yup. For every 1 ppm FC you added with Dichlor, you raised the CYA level by 0.9 ppm. That's how you got to over 100 ppm in CYA level. Of course, letting your FC go down from 3 to less than 1 isn't good even at lower CYA levels.

The Nature2 system is normally a copper ionization system, but is the Nature2 "filter" also adding copper to the pool? If it was, then it obviously wasn't adding enough to keep algae from growing.

In addition to answering mr_clean's question about pool pump runtime, also be sure and brush your pool. As for phosphate remover, it's going to be really hard to know how much to add -- you can test for phosphates, but as you kill the algae with chlorine (yes, you still need to shock with chlorine, but need "help" with the phosphate remover to stop its growth) the phosphorous in the algae will get released (eventually broken down into phosphates as algae food). So I would measure the phosphates and then add 50% more or perhaps even a double dose -- but that can get expensive.

Perhaps "pool tech" can help out here as he has had pools turn bad and used phosphate remover to help clear them up. He might know how much to add.

Richard
carlj0599

high cya and water restriction

Postby carlj0599 » Mon 20 Aug, 2007 20:31

sand filter usually runs 24/7 and definitely has been for the last 3 weeks....when the algae started was after covering pool with solar cover for the first time and turning off filter for 10 hours....

back on that fateful weekend i noticed on Sun that pool was looking a little cloudy maybe even a tinge of green/yellow....i added one bag of shock on Sunday night and let filter run all night....put solar cover on Monday morning...turned off filter....came home Monday afternoon and pool was more cloudy and greenish yellow.....i turned on the filter and shocked....did not put cover back on and let filter run 24/7 since....thu/fri of the week added algaecide (Banish)....put entire bottle in (I think 20oz).....since then have been adding shock every 1-2 days and brushing morning and night.....i've been in pretty much a holding pattern since then....not getting worse, not getting better

well, the Nature2 brochure says that the filter contains silver and copper although it does not state whether or not it is 'adding' copper to the pool, but i'm going to assume the answer is yes....i see also that copper algaecides should not be used with this filter...i assume b/c it will raise the copper too much or screw up the filter itself....also of note, I'm using a Nature2 Express Cartridge....which says it treats up to 25000 gallon pool....until recently i realized i have a 26700 gallon pool...is the additional 1700 gallons negligible?....
chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2382
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

high cya and water restriction

Postby chem geek » Mon 20 Aug, 2007 20:52

Yes, the reason the Nature2 cartridge says to not add algaecides with copper is that additional copper could lead to precipitation as....drum roll please...blue-green copper carbonate. In fact, even raising the pH can cause the copper to precipitate. That's the main problem with using a copper system for algae control.

By the way, BioGuard Banish is a copper algaecide -- some metallic copper, but mostly copper sulfate. So I strongly suspect you may now have copper carbonate instead of algae or in addition to algae. The Cal-Hypo shock would initially raise the pH and would precipitate out the copper if it was "on the edge" and the Banish would add extra copper which would also precipitate out more copper carbonate. On the other hand, green algae is also green.

Here's one easy way to tell if you've got algae or just copper precipitation. Add some chlorine (Cal-Hypo or bleach or chlorinating liquid) at night after the sun is off the pool and let it mix with the pump running for at least 30 minutes. Then measure the chlorine level accurately (a FAS-DPD chlorine test is best for this -- such as the Taylor K-2006 kit found at Taylor here or from Leslie's or the even better TF100 test kit from tftestkits here ). Then measure the chlorine again the next morning before the sun hits the pool (or as early as you can). If you measure minimal chlorine drop (< 1 ppm FC), then you've only got copper precipitation and not algae in which case removal of the excess copper by using a flocculant (OMNI Liquid Floc Plus) and then vacuum to waste would work and then lower the pH to dissolve the rest of the copper to keep it in solution. If instead you measure a significant drop in FC overnight, then you've got algae.

Even with your high CYA level, the fact that you may have copper in the pool is a good thing as that is an algae killer that may let you get away with shock to kill the algae -- so perhaps it's already dead (which would look gray cloudy) and it's simply the high pH and the extra copper that is precipitating the copper (which would look blue-green). See this post to see what copper carbonate looks like. Over time, this often turns into black copper oxide which may be seen at this post so that copper stains can be from blue-green to black.

By the way, you should also measure your TA level since if it's high, then that will also lead to more copper carbonate precipitation in which case you can lower the TA by following the procedure in this post.

Given the addition of Banish, I'm fairly certain the algae is dead and you've now just got copper carbonate precipitated. So use OMNI Liquid Floc Plus to consolidate most of it, vacuum to waste, and after that, adjust the pH down which should help keep the copper in solution. You might consider using a different system other than Nature2 at some point unless you want to potentially deal with this again.

Richard
carlj0599

high cya and water restriction

Postby carlj0599 » Mon 20 Aug, 2007 22:01

ok, interesting information...

the test kit i purchased this weekend only goes up to a measure of 5 FC which means I'm unable to tell whether its dropping at this point other than by judging color. I checked FC this morning and then tonight with the purposes of comparing color....i don't believe it went down as both times the color was a bright magenta/deep pink color....could i save a sample from PM and compare to color in AM to get a better visual comparison? also, my pH is 7.8 as of this evening...

in addition to the cloudiness, i brush the yellow/brown dust from the floor and steps every time i brush...that's what makes me say that i'm in a holding pattern....i brush it off, it returns within a few hours...and this has continued for the last two weeks....i will return to store and ask them to check copper....i also have not backwashed in two weeks in support of the theory that a dirtier filter cleans better....pressure is just now 10lbs above norm on filter and flow is still decent...
carlj0599

high cya and water restriction

Postby carlj0599 » Mon 20 Aug, 2007 22:24

wow, first off thank you so much for taking the time to respond...you have given me more knowledge in the last two days...i really appreciate your time and help....

back to the fateful weekend.....my pH was down to 6.8.....i added the necessary soda ash to raise the pH to 7.2 and just after that is when i noticed the cloudiness....AH-HA!!! Perhaps i experienced the copper precipitation as a result of that initial raise of pH?

so perhaps i need to follow your methodical approach here...figure out if the copper has precipated....if so, use floc, vacuum and see whether algae exists...

as for the posts of what copper carbonate looks like, i have not noticed anything like that in the pool (at least in the shallow end)....i cannot see the main drain due to the cloudiness....

Return to “Pool Algae & Green Pool Water”

Who is online at the Pool Help Forum

Users browsing this forum: No registered users and 0 guests