New owner, question on free Chlorine levels

[Reese]

Reese and svspa, The 2-3 ppm FC after one's post soak dose is not my recommendation but rather Vermonter's.

We're on the same page, other than my concern that a calculated 2-3 ppm dose may not be enough to leave a 2 ppm residual after the dose works on the stuff that was left behind.  If appears Jeff already discovered that.

[Reese]

... what if the PH is low but the TA is high? or is this even possible?

Sodium bicarbonate (baking soda, TA up) increases both pH and TA, working on TA more than pH.  Sodium Carbonate (soda ash, pH up) raises pH more than TA.

Low pH/High TA, use soda ash
Both low or to build TA, use baking soda.

[jeff925]

Thats , thats pretty much what i found. the 2ppm burned off rather quickly. i needed to add enough for a 4ppm reading so that i was able to maintain a 2ppm reading after about an hour.

i did test this morning and I was down to barely a 1 reading so i added a tad more. my guess is because I was at 0 for 3-4 days there are a lot of contaminents that are using up the FC

i plan to do a Shock of dichlor tomorrow night and i think I will be ok

[Reese]

Thats , thats pretty much what i found. the 2ppm burned off rather quickly. i needed to add enough for a 4ppm reading so that i was able to maintain a 2ppm reading after about an hour. i did test this morning and I was down to barely a 1 reading so i added a tad more. my guess is because I was at 0 for 3-4 days there are a lot of contaminents that are using up the FC  i plan to do a Shock of dichlor tomorrow night and i think I will be ok

Although I agree that a dichlor shock is in order after running for awhile with low sanitizer, the fact that your dichlor reading is down to 1 the morning after a dose is not a reason for concern.  Dichlor dissipates rather quickly -- it is not unusual for a 3 ppm reading to be almost gone within 24 hours.  That is pretty much how the Vermonter method is supposed to work, allowing you to soak in low amounts of sanitizer.  As long as a majority of the chlorine doesn't all disappear in the first couple of hours after a dose, you are doing fine.

[longshot]

Great thread, all.  I just got my first-ever tub up and running last week, so this information is very timely.  Like some others have mentioned, I've been watching my chlorine levels bounce around a bit, and have trying to divine the right routine.  I think I may have started out a bit low, due to conflicting instructions (the bottle of chlorine indicated about 2.5 Tbs, whereas my startup book said 0.5 Tbs - big difference).  In any case, I did get it to the 3-5ppm range.

Next day I checked it and it was at 0.  So I tossed in some more, and it went back up.  Last three times I used it I put in 1/2 Tbs Cl after we got out, put the jets on a 20 min cycle, and put the cover on.  

The question that keeps going through my mind is: how do I know whether I'm doing it right? I mean, apart from reading the test strips, what are the signs that I'm not putting in enough dichlor?  How long does it take them to show up? So far my wife and I have used our new tub every night since we got it up and running last Sunday except last night.

[svspa]

longshot,

Probably the most obvious effect of having insufficient sanitizer is cloudy water. When your water goes bad you'll see it and smell it.

The problem is by the time you can see your water is bad things have been brewing in there awhile. Impossible to tell you long they were there, what type of bacteria, virus, contaminant, etc. it might be. Every tub and situation is different.

That's why to be really safe you maintain a specific recommended level of sanitizer in your tub per some routine. That routine can include something like Vermonter's where you purposely allow the level of sanitizer to drop to zero or near zero for when you soak but then raise it back up immediately thereafter.

It is also entirely possible that you could go without any sanitizer for a week and not have a problem, maybe no bacteria has been introduced into the water or whatever is there is innocuous. But unless you take your water to a lab and have it tested every  day there is no way of knowing.

That's about it, unfortunately we don't have cheap home microbiology test kits that would allow us to know exactly how clean our water is. Measuring your sanitizer is the best we got. As long as you have some you know bacteria can be killed, when it gets to zero you can't tell how far up the unsanitary scale your water has become until it gets cloudy and you have to spend a couple of days cleaning it up. Or worse see a doctor to have some mystery illness diagnosed.

Steve

i did test this morning and I was down to barely a 1 reading so i added a tad more. my guess is because I was at 0 for 3-4 days there are a lot of contaminents that are using up the FC

PS, Jeff makes a good point here. When you have nasties growing in your tub your tub requires more chlorine, or has a high chlorine demand. If your tub is really clean you chlorine demand will be lower and your residual will last a lot longer. If I know I won't be using my tub for a few days I can raise it to 3-5ppm and come back 3-4 days later and still have residual FC. That tells me there is nothing in my tub that the FC needs to kill.  

[Reese]

The question that keeps going through my mind is: how do I know whether I'm doing it right? I mean, apart from reading the test strips, what are the signs that I'm not putting in enough dichlor?  How long does it take them to show up?

The best approximation of a clean tub is the chlorine residual.  If you have most of the dose showing 1-2 hours after, and a measureable amount the next day, the chlorine is staying ahead of any bacterial growth.  As Steve said, when the tub starts getting out of hand, you will notice the chlorine being used up quicker, and eventually, cloudy water, and if things get real bad, a smell.  If that happens hit is with a big dose (10ppm+), and keep monitoring and adding until you are able to maintain a residual.

[longshot]

Thanks for the info on that, all.  Makes sense.  Really comes back full circle to keeping an eye on residual FC and the rate at which we have to add more.  Now I get it (ok, so I'm a bit slow   ).