OCLT Question

[SFowler252]

Do I run the filter all night when running the OCLT?

I found some dark sediment on the bottom of our sparkly pool yesterday morning. We have major road construction going on one block from our home and it just might be dirt. But I decided to do an OCLT just to be sure. So I brought the FC up to 16 last night and turned off the filter an hour later as usual. It dawned on me this morning when I went to do my tests that I probably was supposed to leave the filter on all night. So here are the numbers from this morning:

FC 15.5
CC 0.5
PH 7.5 (before l added bleach to get to 16)
TA 100
CH 250
CYA 50
Borates 50
Water Clear

So it passed but only if it was ok to turn off the filter.

Also, I want to thank the everyone here on TFP for all the great information and rescuing us & our pool from being pooled stored ever again. I found TFP in June when we were having so much trouble after opening our pool in May. Our pool had very high amonia, cya, and copper from the all the shock products, algaecides & etc. that the pool store insisted would clear up our water issues. We followed the info here; bought the TF-100 test kit, exchanged about 2/3rds of the water and used the BBB method to take control of our pool. We now have extra time & money to spend on our grandkids & our backyard oasis!

I really enjoy reading and learning from all of the posts here, so I decided became an offical member, the least I could do for the ultimate end result.....a sparkling, clean pool from now on! Except my DH now says I am obessed with the pool! But it's wonderful to be able to enjoy our pool and to know without a doubt that the BBB method is all we will ever need.

Thanks everyone and have a great day in your pool!

 

[mynewpool]

From what I have read on here, anytime you are shocking, which is what I assume you are doing, the pump should be running 24X7 until you are done shocking.

 

[linen]

Welcome to tfp, SFowler252

I like to leave the pump on during OCLTs, but if you do turn it off, make sure the pump is on for ~1 hour before doing the morning measurement. I would probably repeat your OCLT tonight with the pump running just to be sure.

 

[SFowler252]

I knew, after the fact, that I should have left the filter going overnight for the OCLT. Thank you for confiming. Especially since I brought it up to shock level. But thought if I had a problem, I would be a head of the game.

I only had to add my normal amount of bleach yesterday and last night to get the fc back to 16. I left the filter running overnight. I only lost .5 of FC, 0 cc, and clear water; so it passed. Whew! Must have been only dirt. Well it's raining today and the temps are dropping this week so I will let the FC drop back to 6. With the weather changing, it won't imterupt our swimming. I know we can swim up to shock level but I'de rather the little grandkids didn't.

But now that I have brought the FC to 16 the stains from using copper algaecides, previous to changing to the BBB method, are back. Will they go away if I add more sequestrant? I sure hope so.

Thanks for the advice!

 

[yeggim]

...

But now that I have brought the FC to 16 the stains from using copper algaecides, previous to changing to the BBB method, are back. Will they go away if I add more sequestrant? I sure hope so.

Thanks for the advice!

Once your Chlorine level drops below 10 ppm, test your PH and adjust to 7.2 Adding more sequestrant with a lower PH should clear it up.

If your fill water is good and with a pool your size it would be cheaper to address your metal problem by replacing some water. Since it's late in the season and you already have sequestrant, it probably will be easier to wait and address next year.

 

[SFowler252]

Thanks yeggim for the tip to lower the ph to 7.2 after the fc drops.

It is getting late in the season and will be lowering the water level to close in a few weeks. Hoping it's more that a few weeks though. I am not ready to see fall come yet.

I wonder if the metals in the water will cause staining this winter when it's closed? I may replace some water before we close just to be safe. Any thoughts?

 

[yeggim]

Thanks yeggim for the tip to lower the ph to 7.2 after the fc drops.

It is getting late in the season and will be lowering the water level to close in a few weeks. Hoping it's more that a few weeks though. I am not ready to see fall come yet.

I wonder if the metals in the water will cause staining this winter when it's closed? I may replace some water before we close just to be safe. Any thoughts?

That's a good idea. There's no way of knowing what will happen over the winter. If your fill water is good, the more water you replace, the better. I closed real late last year with the water temp in the mid 40s. Used the last of my bleach and covered with a Chlorine level of 12 ppm with a CYA level in the 40 to 50 range. I was swimming three days after opening. It might be a good idea to do something similar to keep from having to add shock levels of Chlorine to get through the winter.

Polyquat 60 is the only algaecide that's recommended here. A good many folks close their pools with it. Folks battling metals use it to keep algae at bay during ascorbic acid treatments for metal stains. Closing with cold water temps, mid range Chlorine levels and some Polyquat 60 should give you the best chance of avoiding any metal stains. All that said, you will be better off replacing as much water as you can before closing. I have the same size pool as yours so draining and replacing half your water goes pretty quick and should do the trick.