No need to check anything else right now ... CYA, TA, CH do not typically change very fast and pH is not accurate with FC >10ppm.
can't hold a chlorine reading
- Thread starter mdreese
- Start date
Life is good!! FC held last night and CC was .5 last night and this morning! How long does it take for the FC to drop? It was 22. This time of year we aren't getting a lot of sunshine but the temp is in the 60's. Forecast is for mostly cloudy throughout the next week. I'm assuming based on the reading that I wait till the FC drops below 10ppm and fully test the water. I will be turning the heater on in the pool also in the next day or 2 since it takes a while to heat up 22,000 gallons. Hopefully swimming by Memorial Day! Are my assumptions correct? Also does heating the water ( prob 85) utilize more chlorine? Thanks again for all the help. I went through probably 25 gallons of bleach, but the cost saving from bags of shock was tremendous.
Greetings fellow pool owners! After a very long winter (and spring) I have a nice 68 degree day and have opened the pool. I tried to open last week but it got too cold over the weekend and all efforts were lost but I did put some pucks in the chlorinator hence the CYA level. It was crystal clear today with no smell. I tested my water and got the following:
FC .5
cc.5
pH 6.9
TA 120
CH 220
borates 50
CYA 50
I used the pool calculator to add bleach for shock levels plus borax for the pH and tested them an hour later. These are the readings
FC 6
cc 3.5
pH 7.5
TA 170
So here's my question. I don't know if I ever got to a shock level of 15 since I didn't test it immediately...should I? and why is it dropping so fast? This is only my 2nd summer with BBB so I'm not an expert by any means. Last year I added the bleach and the numbers were in the 20's. I use walmart bleach and it says 8.25% so i used that in the calculator with the 128 oz jug. Is that correct? Comments?
FC .5
cc.5
pH 6.9
TA 120
CH 220
borates 50
CYA 50
I used the pool calculator to add bleach for shock levels plus borax for the pH and tested them an hour later. These are the readings
FC 6
cc 3.5
pH 7.5
TA 170
So here's my question. I don't know if I ever got to a shock level of 15 since I didn't test it immediately...should I? and why is it dropping so fast? This is only my 2nd summer with BBB so I'm not an expert by any means. Last year I added the bleach and the numbers were in the 20's. I use walmart bleach and it says 8.25% so i used that in the calculator with the 128 oz jug. Is that correct? Comments?
With a CC that high ... you DEFINITELY need to go through the shock process. Could be some of the CYA from last year was converted to ammonia giving the high CC(?)
Actually the 8.25% jugs are only 122 oz
Actually the 8.25% jugs are only 122 oz
I have no idea if the CYA was converted....how would I know. So with the calculator should I use it at the 8.25 and add more for the oz differences from 122 to 128? Do you test right after adding to see if you are at a shock level or assume you are there? BTW the pool is 65 degrees and crystal clear....can't see anything growing but I agree with the cc being that high
When you put the % at the top, the calculator will tell you how many OZ to add ... that does not change regardless of the size of the bottles you use. You just can not hover over the OZ and have it tell you the # of bottles to use at the top because the sizes have changed.
You should test every hour or so (only FC and CC) and keep adding chlorine to try to stay at shock level.
You should test every hour or so (only FC and CC) and keep adding chlorine to try to stay at shock level.
No. Keeping your chlorine at shock value is all you care about until...
1.Your pool water is sparkling
2. Your CC's are .5ppm or less
3. You can hold your FC overnight without losing more than 1ppm.
Thanks for the help!! It seems to be working. I am holding a chlorine level longer and the cc has gone down to 2! Here's a chemistry question if anyone has time...what actually happens to the chlorine. I know it has to change somehow because chlorine is an element right...it can't just disappear...so where does it go and why does it disappear faster with sunlight?
mdreese said:
Great question. Here's the short version: when you put bleach in the water, a chemical reaction takes place that creates (among other things) hypochlorous acid (HOCL). It is this compound that does the cleaning work in the pool. UV radiation breaks this compound up easily, so it's not that the Cl atom disappears, it's the cleaning power of the compound that disappears.
If you'd like more reading (warning! do not swim into the deep end unless you're really interested!!), read this and this.
Took me several reads of Chem Geeks info to get it
but thanks for the info. BTW I hope bleach is not on the FBI's watch list. Having just made my 4th -12 bottle purchase of bleach from Walmart, I could easily be accused of stockpiling.....sad thing is I'm not stockpiling...I have probably used 35 bottles already in this process Is this what the pool stores refer to as chlorine lock? Way back when their little machine(ALEX) would tell me I need 125 bags of shock to break the "chlorine lock".
but thanks for the info. BTW I hope bleach is not on the FBI's watch list. Having just made my 4th -12 bottle purchase of bleach from Walmart, I could easily be accused of stockpiling.....sad thing is I'm not stockpiling...I have probably used 35 bottles already in this process Is this what the pool stores refer to as chlorine lock? Way back when their little machine(ALEX) would tell me I need 125 bags of shock to break the "chlorine lock".
No. Chlorine lock is usually their answer when the CYA is way too high and it seems like the FC is not doing anything, because they do not understand the CYA/FC relationship.
You just have a lot of something breaking down. Was you cya higher last year? The high CC could be a sign of the CYA converted to ammonia.
You just have a lot of something breaking down. Was you cya higher last year? The high CC could be a sign of the CYA converted to ammonia.
I'm a little confused with what is going on with my pool. I hadd the pool at shock level and it held overnight. the pool is clear and sparkling and the cc were .5 or below. So I assumed the bleach had broken down the ammonia and whatever else was in it. So I uncovered the pool this morning and took a chlorine reading and when I added the powder it stayed completely clear....I did it twice with the same results. I also checked with a quick reading and again not a hint of yellow. I added the reagent to the first sample to check for cc and again no color. Is this normal. Where do I go from here. At the last reading yesterday it was 17 and had held that overnight,
If it just held at 17 overnight, how is it zero this morning? That is contradictory.
It held at 17 the night before plus had the 0 cc and is clear. I assumed it was good and didn't check chlorine levels since yesterday (i was away) so I checked this morning and now it's 0. Should it have gone from 17 at 10 yesterday morning to 0 today?
Here's the latest. At 11:00 my FC and CC were 0 so I added enough bleach to go to 7 since I had already completed the shocking process. At 2:30 the FC was 5.5 and the cc .5. At 5:15 the FC was .5 and cc .5 . It has been 80 degrees, sunny/cloudy and very humid. LOTS of tree pollen. The water is 80. Is this a normal loss? The cya is 35. Seems like last year my levels stayed higher longer but I also had higher cya levels. I leary of more cya since I had trouble with high levels of it last year and it turned to ammonia over the winter.
Would you recommend adding stabilizer? Doesn't it take a week to fully register the amount? I'm open to ideas. Should I go back to shock levels and see if it holds overnight again?
You can try. I continually pass the OCLT myself and feel my FC loss is excessive during the day even with the CYA at 45ppm ... starting to raise it more, although I plan to go SWG soon, so higher is fine with me.