Friend's new pool

[jmcdtucson]

My friend just bought a house with a pool. Pool was clear when they looked at the house but by the time they moved in it was green. He shocked it and that helped, but it was still very cloudy (3-4 ft. visibility).

18,000 gallon in-ground plaster pool with no SWG.

I took my TF-100 kit over and got these readings

CYA: 35
FC: 1
CC: 1.5
TA: 100

I didn't get a Ph reading unfortunately. I'm also a little suspicious of my CYA reading as it seems to be reading low this year (regents are one year old) and tests from the pool store and a pool guy registered from 60-100. He has a Taylor kit on order and we'll double-check tomorrow.

He added about 4 gallons liquid chlorine to bring it up to SLAM level (we did the math on PoolMath). The next day it was down to 7 ppm. The water looked better (maybe 6 ft. visibility). Then he added another dose (same amount) this morning at 10am. 3 hrs. later it was down to 1 again (his measurement, but I'm sure he got it right).

Is it possible for a pool to drop about 18 ppm in 3 hours?

He's of course worried about whether this is working. I think the SLAM should continue. Any thoughts?

Also he's away for a month so is getting this company to take care of the pool. We got a good reference. Any one know about it? They use chlorine gas.

Thanks!

 

[kimkats]

Trust YOUR test results or his when his kit comes in.

The SLAM does work.

His FC is dropping because it is work HARD to clear his pool. Tell him to keep it up.

Show him this link so he can SEE that TFP knows what it is talking about.

Recovering my old inspirational links

I have no idea about the company or what they use so will not comment on it.

Kim

 

[BoDarville]

Trust your test results over the pool store's. It's not unusual for the pool store to measure CYA significantly higher than it actually is - it's happened to me in the past.

Chlorine losses like you have described are not unusual during the initial part of the SLAM Process. Those losses will become smaller as the pool clears up. Keep in mind that the most important part of the SLAM is the M for Maintaining the chlorine as close to the SLAM target as possible throughout the entire process until the 3 criteria of Done are met.