Opening pool

[PeterDM]

Weather has been atrocious here ... but opened the pool about 4 days ago. Put in about a gallon & a half of liquid chlorine & the murk has cleared up with the water more or less clear. Did not have my PH & FC solutions until today (ran out at the end of last season). Tested the FC which had dropped to 1. The PH is high - 7.8 + which is typical for my water. There's no prospect of the pool actually being used in the next week or two due to continuing unseasonably cold weather. So ... what is the correct sequence of testing & adjusting the water chemistry going forward?

Thanks!

 

[Msch99]

Test everything initially and post results, then the experts can give advice.

 

[Texas Splash]

Yes, definitely post some test results. Take advantage of that chilly water now while you can to avoid algae and get everything balanced.

 

[PeterDM]

FC 10 or more (did not do drop test as I added significant amount of chlorine a couple of hours ago)
PH 8.2 or more
CYA less than 20
TA 70
CA 150

Vinyl pool. 12' x 24' x 5' (40,000 litres if I remember correctly)

 

[Texas Splash]

You have a couple things you can do right away. First, get a sock soaking with stabilizer to increase the CYA to at least 30. That should work for a while. While that's soaking, use muriatic acid to lower the pH to the mid-7s. Use 7.8 as a target at first. For example, when using the PoolMath tool or APP, show a current pH of 8.2 and goal of 7.8 and use the recommended amount of acid. Test the pH again in about 30 min or so and adjust more as needed. Doing it in stages this way you won't overdose the pool with acid and go too low. A pH of about 7.5-7.6 should work well for now.

 

[PeterDM]

Complete tests using drop test for FC, CC & TC:

FC 6
PH 8.2
CYA less than 20
TA 70
CA 150
CC 0.5
TC 6.5

I don't have any muriatic acid on hand. I do have some stabilizer pucks. I also have some HTH pucks. For the last two years I have only used liquid chlorine & don't believe that I have ever added stabilizer. The CYA levels were around 30 - 35 last year - did not seem to change noticeably over time. I typically have to lower the PH two or three times during the summer.

 

[PeterDM]

OK. I put two stabilizer pucks in a sock in front of a jet overnight. After about 16 hours the pucks look to be about half dissolved. I took another CYA reading - it has not noticeably changed from before adding the stabilizer pucks - which is to say the dot is still visible when the tube is filled.

I have no more stabilizer pucks. I am wondering if I should use of chlorine pucks rather than liquid chlorine for a while to help add some more stabilizer?

Checked the FC level this morning - it is in the 5-10 range. The pool has the solar blanket on permanently at the minute - there is no prospect of the pool being used for at least another week.

Picked up some muriatic acid. How should I add it? How much should I add?

Thank you!

 

[Texas Splash]

Your FC seems to be holding okay for now, so if you wish to use more pucks that's fine. Once your CYA hits the 30-40 range I would stop.

For the muriatic acid, carefully and slowly pour the required amount near your return jet(s) with the water movnig well. I put my pump on high for acid. Careful of splashing and wind direction (fumes & eyes). Once you add the required amount per PoolMath to lower it to 7.8, give it about 30 minutes and test again. Repeat as necessary to get your pH back to the mid 7 range.

 

[PeterDM]

So ... I apparently added too much muriatic acid - the pH is now below the 7.2 level. It generally always works its way up over time, but so far, after about 5 days, has not shown any sign of that. Should I just leave it as is for a couple of weeks?

CYA is still reading below 20 after dissolving two stabilizer pucks & a couple of chlorine pucks. The FC level seems to be holding fairly well though - the water is still pretty cold (around 20 C) & the pool is covered with the solar blanket 24/7 as it's too cold to be used for swimming. Is continuing to add chlorine via pucks an acceptable way to gradually increase the CYA level, or should I go out & buy some more stabilizer pucks?

 

[Fast7]

the pool is covered with the solar blanket 24/7

This is the reason your pH is not raising back up.