Vacation fc FAIL

Trp3383

Member
Nov 7, 2019
19
08210
Well 2 weeks after getting going with my first spa I went on vacation for a week. I left it with 9ppm fc and when I got back it was as zero and a little cloudy. I started Slam today aiming 20ppm fc at 9:30 am and since then I've added a total of 17oz of 10% bleach between 4 intervals. I believe I'm doing it correct but it seems like the fc is dropping around 6-7 ppm every 3 hours.

Fc 13
Cc 1
Ta 50
Ch 50
Ph 7.4
Cya 50
Borates 50
 

Trp3383

Member
Nov 7, 2019
19
08210
32 hrs in and it's still eating chlorine. The water is clear but fc keeps dropping about 5 ppm every 3 hrs. I'm using pool essentials 10% but it's been sitting in my garage for about 6 months. I wonder what the actual percentage is now.....
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
I'm using pool essentials 10% but it's been sitting in my garage for about 6 months. I wonder what the actual percentage is now.....
I'm sure it degraded a bit by now. If you are assuming the FC reached your goal just because the PoolMath tool (or APP) stated to use X-amount of 10%, you may want to verify the FC about 15 min after running and mixing. That could be what's holding you up a bit.

 

dlleno

Well-known member
Sep 9, 2016
101
denver, CO
Sounds like you are losing fc at am very high rate. Without the calcium problem associated with the refill i would normally suggest an ahhsome purge but given the difficulty you mention let me make a couple of suggestions based on my experience (this has happened to me too).

Slaming works but proof of the pudding is in the eating which means it may take many days and lots of bleach to kill the bad guys that have taken up residence in your pipes and equipment. I see two alternatives to a full on purge (which may be necessary anyway but hold that thought for now)

1. You could decon. The biofilms will be attenuated by 50 or 100ppm decon procedure and that might give the slam a head start

2. I have personally recovered from a vacation situation with an interesting product from the makers of ahhsome, known as hot tub serum. This stuff is a micro purge that is intended to be used weekly for maintenance although i find that it works well as a rescue product that aids the slam. I have performed controlled experiments and found that this stuff realky does improve sanitizer decay rate, in and of itself, avoiding a purge. Its also a great way to extend the chlorine dose interval when leaving for vacation which i just recently did as well . My spa was squeaky clean after 8 days when i dosed with the serum before i left.

I have found there is no substitute for a good purge but that this serum stuff is effective both as rescue after and a preventive prior to vacations
 

Trp3383

Member
Nov 7, 2019
19
08210
Sounds like you are losing fc at am very high rate. Without the calcium problem associated with the refill i would normally suggest an ahhsome purge but given the difficulty you mention let me make a couple of suggestions based on my experience (this has happened to me too).

Slaming works but proof of the pudding is in the eating which means it may take many days and lots of bleach to kill the bad guys that have taken up residence in your pipes and equipment. I see two alternatives to a full on purge (which may be necessary anyway but hold that thought for now)

1. You could decon. The biofilms will be attenuated by 50 or 100ppm decon procedure and that might give the slam a head start

2. I have personally recovered from a vacation situation with an interesting product from the makers of ahhsome, known as hot tub serum. This stuff is a micro purge that is intended to be used weekly for maintenance although i find that it works well as a rescue product that aids the slam. I have performed controlled experiments and found that this stuff realky does improve sanitizer decay rate, in and of itself, avoiding a purge. Its also a great way to extend the chlorine dose interval when leaving for vacation which i just recently did as well . My spa was squeaky clean after 8 days when i dosed with the serum before i left.

I have found there is no substitute for a good purge but that this serum stuff is effective both as rescue after and a preventive prior to vacations
Thanks for the suggestions. Yesterday I tested 15 mins after adding the 10% chlorine amount shown in the app, it wasn't actually hitting 20ppm. The 10% bleach lost it strength sitting on the shelf and is acting like a 6% bleach. I shocked to 20ppm all day yesterday and last night at 1030. This morning at 830 I tested and it was at 18.5ppm, so only lost 1.5 ppm over 10 hrs. The water is clear and my cc is at 1ppm.
 

dlleno

Well-known member
Sep 9, 2016
101
denver, CO
While no substitute for real data on your spa, a good rule of thumb suggests 25 percent sanitizer decay over 24 hours. In actual practice i find that this is reasonable when measured at common usable levels, i.e. 3 ish ppm. It sounds like you're close.

I had an interesting experimental result with that serum stuff where my water was clear and close to the decay rate rule of thumb, and i got an improvement in the decay rate just by using the serum for a week (without slaming)
 

jseyfert3

Bronze Supporter
Oct 20, 2017
681
South-Central WI
Yea, I dont feel like draining it, because I'll need to purchase another vanishing act to get the ch down.
How high is your fill water CH? If it's anything sort of reasonable, you don't need to bring your CH down. I punched your numbers into poolmath and assuming a temp of 104 °F your CSI is -1.15 from your first post. If your CH was 300 (that's about the level of my fill water) your CSI is -0.39.

Since you don't have a gunite/tile spa, low CSI is no concern, but there's no reason to lower CH unless your CSI is 0.3 or higher.

Unless I'm missing something, it would appear you're lowering the CH for no reason.

Also I'm curious from the TFP chem gurus what Vanishing Act is doing, I thought CH couldn't be removed short of changing water with lower CH or RO.
 

dlleno

Well-known member
Sep 9, 2016
101
denver, CO
Im aware of a phosohate buffer product from bioguard that precipitates CA out and makes a grand mess in the process. I used to run my spa with 100 percent ion exchange soft water with no measurable ca. That avoided the mess lol
 

Trp3383

Member
Nov 7, 2019
19
08210
How high is your fill water CH? If it's anything sort of reasonable, you don't need to bring your CH down. I punched your numbers into poolmath and assuming a temp of 104 °F your CSI is -1.15 from your first post. If your CH was 300 (that's about the level of my fill water) your CSI is -0.39.

Since you don't have a gunite/tile spa, low CSI is no concern, but there's no reason to lower CH unless your CSI is 0.3 or higher.

Unless I'm missing something, it would appear you're lowering the CH for no reason.

Also I'm curious from the TFP chem gurus what Vanishing Act is doing, I thought CH couldn't be removed short of changing water with lower CH or RO.
Caldera recommends ch between 25 and 75 with their salt system. I keep my tub at 100
 

jseyfert3

Bronze Supporter
Oct 20, 2017
681
South-Central WI
Caldera recommends ch between 25 and 75 with their salt system. I keep my tub at 100
A more knowledgeable user can chime in, but this doesn't sound like it's needed. It sounds like the recommended level ranges that you get in pool/spa manuals, which we at TFP know are not really correct (and at times, actually impossible to maintain).

A quick search here shows people with 450+ ppm of CH and SWCGs. Like most things, it appears the absolute CH doesn't matter, only the CSI (of which CH is only one component). It appears you want to keep the CH below 0 so scale doesn't form on the plates, but you could probably use straight fill water and have a CSI below 0 (as I pointed out above, with your water parameters a CH of 300 would still be a CSI of -0.39, well below the scaling point of 0).

Anyhow, I'm not telling you to do something one way or the other, just trying to make things easier for you. :)

Full disclosure, I don't yet have a SWCG, but I plan to get one for the spa that comes with our house we're buying and eventually for our pool as well. While I don't yet own a SWCG, once I do I will ignore all manufacture water specs except recommended salt level and follow TFP water specs instead, the same as I currently actively ignore the (incorrect) water specs that come with my Intex spa, like the one to maintain TA at 60-120 ppm. That's impossible in a spa with any sort of aeration! My pH isn't steady at 7.8 or below unless my TA is 40-50 ppm, so trying to maintain the TA at or above the "minimum" level, let alone at the "ideal" level of 80 ppm is simply impossible and doing so is as effective as a dog chasing its own tail. Sure sells a lot of pool chems and frustrates people that haven't found the magic of TFP though.
 

dlleno

Well-known member
Sep 9, 2016
101
denver, CO
Did you ever have a problem with foaming in that older spa? A bit of calcium helps avoid foam.
yea I eventually got tired of the foam issue and quit using the phosphate buffer. the results were interesting though -- the feel of soft water with no measurable calcium is pretty cool, but in the end the cost of the buffer, and the anti-foam required, were not worth the trouble. But if you really want to remove calcium you can use such a product if you want to deal with the mess. Very high calcium in the tap water for me means a water softener, so I ended up (instead of filling with 100% soft water) using a proportion of soft and hard water to get 80 ish ppm
 

Trp3383

Member
Nov 7, 2019
19
08210
Ok so after slamming for over 24hrs everything was clear and good. 2 weeks later still clear. But CC is bownat 3ppm. Do I need to slam again after only 2 weeks?