New; Cloudy pool question.

[BigPoolowski]

I'm a new pool owner, and I just took over from the "pool guys" after they opened the pool. 27k gallons, in-ground plaster, DE filter. I had armed myself with the TFP testing kit and read through pool school. When the pool guys were done, they left the pool as follows:
Temp: 74F
CYA: 70-80
pH: 6.8
FC: 20 (same TC)
TA: 100
CH: 275

Figuring the pH needed to come up, and the pool might as well have some borates, I added 3 boxes of the 20-mule borax. The following day, the numbers were the same except pH now 7.5 and FC down to 17.

The curious part is that before I added the borax, the pool had been crystal clear for four or five days (prior to that, in the first few days after they pulled off the cover, it was variously green/cloudy). Now, over 24 hours later since adding the borax, it's cloudy. I can still see the drain at the bottom of the 8-foot-deep end, but just barely. Any thoughts on this? I read some threads that seemed to scoff at the idea that borax can cloud water, but I'm not sure what else changed.

I figure at this point, I'll maintain the chlorine and hope it clears up? Any other suggestions?

Thanks in advance...

 

[karmabiker]

Welcome to TFP!

Is the testing from your own test kit?

I'm not sure its the borates that actually caused the cloudiness, I suspect there is something with the pH and CH.

How are you chlorinating?

 

[BigPoolowski]

Thanks for the welcome--having a chemistry background myself, the TFP approach struck an obvious chord. Yes, I tested using my own new TFP test kit. At the time I did the tests above, all the chlorine was whatever the pool guys used, presumably some sort of pool store stabilized granules. I have a stash of clorox now, and have switched to that going forward.

Offline, I was advised to backwash the DE filter, which I haven't done yet. I have no idea how the pool guys left things with the filter, and I don't even know what the baseline pressure is supposed to be. Seems like it wouldn't hurt to backwash it.

Your suspicion about pH and CH is my leading theory, but the CH didn't seem all that high--I retested it a couple times, finding that the endpoint of the titration is not all that clear, but it's definitely somewhere between 250-300.

I have good cheap city water, so I'm fairly indifferent to replacing half the water in the pool--that will lower CH and the CYAs while I'm at it. I figure if I can't beat the cloudiness I'll give that a shot.

 

[karmabiker]

Read the DE Filter Cleaning Tutorial before you backwash.

If it was backwashed and not reloaded you may be seeing things in the water the filter would be catching.

 

[BigPoolowski]

Just reporting back to close the loop on my question: Within about 48-60 hours of adding the Borax, the water turned clear again. I didn't do anything special, and all the other numbers are essentially the same. I'd be open to the possibility that adding a lot of Borax at one time to a pool can lead to temporary cloudiness. Interesting to note.