No matter how much we shock no chlorine registers....

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

No matter how much we shock no chlorine registers....

Postby Sick of Green » Tue 23 Jun, 2009 20:50

Our pool is a pear shaped, 30 ft long, 8ft to 3 ft vinyl inground that holds 22,000 gal. We were fools (now we know) for not covering our pool this past winter...now we have been attempting to get it together for 4 wks now. AHHHHHHH!! So frustrating, it was all jacked up! Finally everything is where it should be EXCEPT chlorine just won't stick!

See our levels below.

FC: 0
TC: 0
pH: 8.0
TA: 90
CH: 210
CYA: 100+
Pool chemicals: shock, algaecide, granular chlorine
My pump & filter: DE filter

Just today we added 5 bags of shock & an hr later we tested the water, there was none!! Total (our water still has not cleared enough to see the bottom & we have green algea) we have dumped over 50 lbs of chlorine & still no results. I am more than confused!!!

(Yesterday thru today) The most recent order of steps was 1. add 4 packs of shock 2. 4 hrs later add algeacide 3. 12 hrs later shock again- 4lbs 4. 4 hrs after that, add 4 more lbs of shock

ALL THIS AND OUR POOL STILL LOOKS LIKE 1000 NEWBORNS HAD THEIR 1ST BM WHERE OUR POOL USED TO BE! I don't know what else to do, we have spent sooooo much $$ that we're considering draining it completely and just starting from scratch. The weather here has been approx 88+ deg and water temp is 80 right now but we cannot enjoy. Please help!
Sick of Green
 

No matter how much we shock no chlorine registers....

Postby chem geek » Tue 23 Jun, 2009 21:14

What kind of chlorine are you using to shock your pool? If it's Dichlor, then you are increasing your CYA level way too much. For every 10 ppm Free Chlorine (FC) added by Dichlor, it also increases CYA by 9 ppm. If it's Cal-Hypo, then for every 10 ppm FC, it also increases Calcium Hardness (CH) by 7 ppm.

With a very high CYA level, the added chlorine will not be very effective. You should dilute the water by partial drain/refill (multiple times) to lower the CYA level. You could use a copper-based algaecide to kill the algae, but then will risk staining your pool and you'll still have a high CYA level to deal with, so I would just bite the bullet and dilute the water.

Read the Pool School to learn how to manage the pool without having the CYA climb so high and to prevent algae growth using chlorine (i.e. maintaining a sufficient FC relative to CYA).
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No matter how much we shock no chlorine registers....

Postby Sick of Green » Wed 24 Jun, 2009 00:16

how much water should be drained from the pool? would it be wise to drain half way of a 22,000 pool? and then refill?
Sick of Green
 

No matter how much we shock no chlorine registers....

Postby chem geek » Wed 24 Jun, 2009 03:07

Since it's a vinyl in-ground pool and since you don't know your water table level, I'd play it safe and drain only as far down as a normal winter closing just below the returns OR you can do a continuous drain/refill by draining from one end or the bottom and filling from the other end at the surface. It takes more water to do the latter. There is also the "sheet" method, but with your large pool that can be difficult. The sheet method uses a very large plastic sheet and drains from underneath while filling from the top with the sheet dropping down as water replacement is made. When you are done, you remove the sheet and the water mixes.

You should probably figure out more accurately your true CYA level, diluting the water with tap water before doing the test and then multiplying by your dilution factor (i.e. if diluted by 50/50 tap water and pool water, then multiply result by 2).
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No matter how much we shock no chlorine registers....

Postby sick of green » Wed 24 Jun, 2009 10:32

Im more than half way draining the pool completely just didnt want to take any chance. Pool has not been clean all year because I couldn't see the bottom. The last people tha closed the pool told me it would be okay not to cover it. Would it be okay if i walked the bottom of the pool to clean it free of the leaves and debris?
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