Newbie - cloudy water after shock

[zack1]

I bought a house with a pool in April. I'm a total newbie, but realized quickly that the water chemistry was a mess (FC 0, TA 10, pH 5, CYA 150, and copper stains everywhere; Copper levels at 0.9ppm). Two weeks ago, I had the water balanced (mostly, the CYA was still high at 110), so I brought the FC down to zero and did an ascorbic acid treatment to remove the Copper stains (followed by addition of sequestrant). This worked great, but because of the high CYA, I didn't get my FC up high enough and on Saturday, I noticed algae growing on the ladder and on a spot on the wall. The water looked a bit cloudy, but just a little bit. The pool is a 33,000 gallon vinyl liner pool.

After reading up in pool school, I began treating the algae on Sunday. I added 4 182oz bottles of clorox bleach (3 in the afternoon and 1 in the evening). The water instantly turned cloudy. I tested the water on Monday morning.

Monday Morning-
FC 8
CC - 1.7
CH - 197
TA - 85
adjusted alkalinity - 40
CYA 104
pH 7.4
(Copper 0)

I added 6 more bottles of bleach - 3 in the morning, 3 in the evening to bring the FC to 32 at sundown. I also added ~15 lbs of NaBicarbonate to bring the adjusted alkalinity up.

Tuesday Morning-
FC - 30
CC <0.5
pH 7.6
TA - 120

After testing, I added more bleach to bring the FC up to 39 (the suggested shock value for a CYA level of 100).


My water looks like skim milk. I hope this is just dead algae, but I'm worried since I have don't have a clue what I'm doing. Can someone with a little more experience tell me if I am on the right track. I hope I haven't done something horrible by adding 12 huge bottles of regular clorox to a pool that was just treated for copper. Is there anything that will accelerate the clearing of milky water, or should I just be patient and let the filter work? How long should it take? Thanks for any info!

 

[Bama Rambler]

Welcome to TFP.

What test kit are you using?

Most probably the cloudiness is from the algae being killed. You need to follow the shock process but your problem is that you don't really know what your CYA is. Most tests report anything over 100 as 100 or close, but it could really be much higher.

 

[zack1]

I have been relying on my pool store for testing, but I am now using the Taylor K-2006 test kit. My CYA level of 100 (104 to be precise) is based on the pool store test. I have been bringing a water sample to the store once a week since I took over this pool in April. The CYA levels were initially 147, but have been slowly going down since April. I'm sure their test loses accuracy at such high levels as well, but I am hopeful that it's not too far off.

 

[Bama Rambler]

Since you have the K-2006 use it to test your CYA. Dilute the pool water 50/50 with tap water and test the CYA, then multiply the result by 2. That'll tell you if you're close to what you think it is.

 

[zack1]

Using the dilution test you recommended, my CYA appears to be even higher (~160 - using the disappearing dot test). Should I attempt to drain some water to bring this down, or should I try to deal with the current algae/cloudy water problem first? Any recommendations are appreciated.

 

[jblizzle]

Unfortunately ... you need to drain drain drain. CYA of 160ppm is way too high to deal with.

Assuming you do not have a SWG, you should try to get your CYA down to around 40ppm before you put any more chemicals in that will just be pumped to waste.

What type of pool do you have? Add all the details you know into your signature.

Most pools should not be drained 75% ... unless it is gunite and you know the ground water table is not high.

 

[zack1]

I don't have tons of faith in the disappearing black dot test that I just did to determine these levels. It's pretty qualitative test - semi-quantitative at best. At least the pool store uses a spectrophotometer to determine the levels, which I find more likely to be accurate. Based on their tests, my CYA levels are dropping by about 25ppm each month (from 150 to 100 since May 1st) and are currently at 100 ppm. I don't want to drain the pool if I can get to 50 ppm by the end of August. Also, I had my water tested at 2 pool stores and get the same CYA reading of 100.

I don't mind draining, but only if its absolutely necessary.

 

[jblizzle]

By most people's accounts here ... CYA is one of the tests that the pool stores are the WORST at. Also, generally the tests only go up to 100ppm, so anything above that get reported as 100ppm ... sounds like both stores are doing that.

CYA do not just drop that much without a lot of water replacement.

The test is not really that hard. These instructions have a link to pictures:
extended-test-kit-directions-t25081.html#p206397

 

[Butterfly]

I agree with Jason You need to start the drain/refill dance to get the CYA under control.

 

[zack1]

OK. All I know about the pool is that it's a 33000 gallon vinyl liner pool. (I could go look at the pump/filter, but I'm assuming that doesn't affect the amount I can drain.) From my tests, I'm guessing that CYA levels are somewhere between 120 - 180. Is it ok to take it down to 25% full?

 

[jblizzle]

Is it above or in ground?

For above ground I have read the rule of thumb is leaving at least a foot of water in the shallow end.
For in ground, there are concerns of what the ground water table level is.

There is also the option of pumping out at one end and adding water at the other ... this requires more water change to get the same effect, but then no risk to liner.

 

[zack1]

It's an in ground pool. I have no idea what the local ground water table is. I guess the safest bet is the simultaneous pump out/ad in method.

 

[jblizzle]

You could certainly drop the water level a foot without much chance of anything bad. Doing that 3-4 times might be less water use than the simultaneous method.

Have you ever dug a hole and found water in it?

 

[zack1]

I have not. But we just moved here, and I certainly haven't dug an 8 foot hole. I'll have to wait until the weekend to do this anyway. For now. I guess I'll keep my FC up until I pass an OCLT - it's holding steady at 39 and the CC has dropped to < 0.5, so hopefully I killed all the algae. I guess I can start changing out the water this weekend.