Newbie needs help with spa water chemistry problems

[Vesuvius]

I've owned my spa for some time but transitioned a few months back to a manual chlorine approach after my bromine-based chlorinator broke and I saw the cost to replace it. I've been having a really rough time keeping my water chemistry in order and could use some advice. In the past, I was using strips for testing, MPS after every soak and some MPS, di-chlor and clarifier weekly, along with whatever was necessary to adjust pH/TA. The water was generally clear but I was getting deposits at the water line and was having a hard time reading the color strip gradations. Then, I screwed up by missing a shock/chlorine cycle after a trip and the water got very cloudy with 0 FC. Took water in to pool company for testing several times and dumped ton of sanitizer in but could not get off of 0 ppm.

So, drained the spa on Jan 24 (unfortunately, I did NOT use Ahhsome or any other system flush before doing so), refilled, bought a Taylor K-2006 kit and did a bunch of reading to better understand how to manage the water. But I continue to have big problems keeping FC in the spa, despite the fact that it's not been used since the re-fill. For example, on Feb 12, I measured 0 FC again and the water was cloudy. Because my CYA was 39, I decided to super-chlorinate with liquid chlorine. I did this over 3 separate additions roughly 45 mins apart, testing every 45 mins, as the liquid chlorine bottle is very old (no date on it but it's been years, not months, since it was purchased for our pool) and I wasn't sure how effective it would be. I ended up adding 41 oz in total for a roughly 500 gallon spa until I finally ended up with 6.0 FC, 0.5 CC, 8.0 pH, 80 TA (adjusted to 56 after accounting for rough 30 ppm borate and 38 CYA), 170 CH and 38 CYA. This equated to a 0.22 Sat Index using the watergram wheel, so pretty good. I then dropped in 1/2 oz Acid Magic in effort to drop pH to 7.8 and bring Sat Index closer to 0. The next morning I checked water clarity and it was clear (maybe not perfect, but close).

I went out today to do the full tests and the water is hazy again and I get 0 FC via strips and via the K-2006. How could it have dropped 6 ppm in just 66 hours (or less--not sure when it dropped to 0) with no usage? I sure would appreciate some guidance here, as I'm so frustrated with the whole thing. Thanks!

 

[Vesuvius]

I've owned my spa for some time but transitioned a few months back to a manual chlorine approach after my bromine-based chlorinator broke and I saw the cost to replace it. I've been having a really rough time keeping my water chemistry in order and could use some advice. In the past, I was using strips for testing, MPS after every soak and some MPS, di-chlor and clarifier weekly, along with whatever was necessary to adjust pH/TA. The water was generally clear but I was getting deposits at the water line and was having a hard time reading the color strip gradations. Then, I screwed up by missing a shock/chlorine cycle after a trip and the water got very cloudy with 0 FC. Took water in to pool company for testing several times and dumped ton of sanitizer in but could not get off of 0 ppm.

So, drained the spa on Jan 24 (unfortunately, I did NOT use Ahhsome or any other system flush before doing so), refilled, bought a Taylor K-2006 kit and did a bunch of reading to better understand how to manage the water. But I continue to have big problems keeping FC in the spa, despite the fact that it's not been used since the re-fill. For example, on Feb 12, I measured 0 FC again and the water was cloudy. Because my CYA was 39, I decided to super-chlorinate with liquid chlorine. I did this over 3 separate additions roughly 45 mins apart, testing every 45 mins, as the liquid chlorine bottle is very old (no date on it but it's been years, not months, since it was purchased for our pool) and I wasn't sure how effective it would be. I ended up adding 41 oz in total for a roughly 500 gallon spa until I finally ended up with 6.0 FC, 0.5 CC, 8.0 pH, 80 TA (adjusted to 56 after accounting for rough 30 ppm borate and 38 CYA), 170 CH and 38 CYA. This equated to a 0.22 Sat Index using the watergram wheel, so pretty good. I then dropped in 1/2 oz Acid Magic in effort to drop pH to 7.8 and bring Sat Index closer to 0. The next morning I checked water clarity and it was clear (maybe not perfect, but close).

I went out today to do the full tests and the water is hazy again and I get 0 FC via strips and via the K-2006. How could it have dropped 6 ppm in just 66 hours (or less--not sure when it dropped to 0) with no usage? I sure would appreciate some guidance here, as I'm so frustrated with the whole thing. Thanks!

One more thing I should add--I did put in 2 new filters when I did the drain and fill on Jan 24.

 

[JoyfulNoise]

Unfortunately it sounds like chlorine demand from biofilms in the plumbing. You’ll need to do an Ahhsome purge and then dump a refill the water.

 

[mgtfp]

the liquid chlorine bottle is very old (no date on it but it's been years, not months, since it was purchased for our pool) and I wasn't sure how effective it would be. I ended up adding 41 oz in total for a roughly 500 gallon spa until I finally ended up with 6.0 FC, 0.5 CC, 8.0 pH, 80 TA (adjusted to 56 after accounting for rough 30 ppm borate and 38 CYA), 170 CH and 38 CYA. This equated to a 0.22 Sat Index using the watergram wheel, so pretty good.

I guess you were quite fortunate to get FC still up to 6ppm. Not just the chlorine demand from the biofilms, but also with such old chlorine. After years, that would be mostly salty water.

And just to clarify Total Alkalinity: All the TFP recommendations are based on TA as it comes from the drop test. The adjustment is really only necessary when doing a manual CSI calculation.
PoolMath (which I would recommend to use generally for all pool related calculations, not just CSI, but also for calculating required amounts of chemicals to be added) does that internally. Much easier and more accurate than the Taylor watergram.

 

[Bperry]

I've owned my spa for some time but transitioned a few months back to a manual chlorine approach after my bromine-based chlorinator broke and I saw the cost to replace it. I've been having a really rough time keeping my water chemistry in order and could use some advice. In the past, I was using strips for testing, MPS after every soak and some MPS, di-chlor and clarifier weekly, along with whatever was necessary to adjust pH/TA. The water was generally clear but I was getting deposits at the water line and was having a hard time reading the color strip gradations. Then, I screwed up by missing a shock/chlorine cycle after a trip and the water got very cloudy with 0 FC. Took water in to pool company for testing several times and dumped ton of sanitizer in but could not get off of 0 ppm.

So, drained the spa on Jan 24 (unfortunately, I did NOT use Ahhsome or any other system flush before doing so), refilled, bought a Taylor K-2006 kit and did a bunch of reading to better understand how to manage the water. But I continue to have big problems keeping FC in the spa, despite the fact that it's not been used since the re-fill. For example, on Feb 12, I measured 0 FC again and the water was cloudy. Because my CYA was 39, I decided to super-chlorinate with liquid chlorine. I did this over 3 separate additions roughly 45 mins apart, testing every 45 mins, as the liquid chlorine bottle is very old (no date on it but it's been years, not months, since it was purchased for our pool) and I wasn't sure how effective it would be. I ended up adding 41 oz in total for a roughly 500 gallon spa until I finally ended up with 6.0 FC, 0.5 CC, 8.0 pH, 80 TA (adjusted to 56 after accounting for rough 30 ppm borate and 38 CYA), 170 CH and 38 CYA. This equated to a 0.22 Sat Index using the watergram wheel, so pretty good. I then dropped in 1/2 oz Acid Magic in effort to drop pH to 7.8 and bring Sat Index closer to 0. The next morning I checked water clarity and it was clear (maybe not perfect, but close).

I went out today to do the full tests and the water is hazy again and I get 0 FC via strips and via the K-2006. How could it have dropped 6 ppm in just 66 hours (or less--not sure when it dropped to 0) with no usage? I sure would appreciate some guidance here, as I'm so frustrated with the whole thing. Thanks!

Save yourself some of that frustration by placing the test strips in the trash bin now that you have an actual test kit. I don’t have a spa but I imagine you can do an overnight chlorine loss test and see if that tells you if there is organics/algae in the plumbing.

 

[Vesuvius]

Unfortunately it sounds like chlorine demand from biofilms in the plumbing. You’ll need to do an Ahhsome purge and then dump a refill the water.

Thanks--makes sense so will do. Do you think I also need to replace those Jan 24 filters or can I put those back in with the fresh water?

 

[Vesuvius]

Save yourself some of that frustration by placing the test strips in the trash bin now that you have an actual test kit. I don’t have a spa but I imagine you can do an overnight chlorine loss test and see if that tells you if there is organics/algae in the plumbing.

Yeah, I just used them today as a double-check on my 0 FC reading via Taylor, as I couldn't believe it.

 

[Vesuvius]

I guess you were quite fortunate to get FC still up to 6ppm. Not just the chlorine demand from the biofilms, but also with such old chlorine. After years, that would be mostly salty water.

And just to clarify Total Alkalinity: All the TFP recommendations are based on TA as it comes from the drop test. The adjustment is really only necessary when doing a manual CSI calculation.
PoolMath (which I would recommend to use generally for all pool related calculations, not just CSI, but also for calculating required amounts of chemicals to be added) does that internally. Much easier and more accurate than the Taylor watergram.

OK, thanks. Will check out the PoolMath app. Is there a good online option for cheap liquid chlorine or does the water weight make it generally more cost-effective to buy from a local pool store?

 

[Mdragger88]

*Trash the strips
* Purge with Ahhsome (throw the filters in too like in the video, no need to buy new ones)

what is ahh-some?

What is Ahh-some?

www.google.com

*Get some fresh liquid chlorine/unadulterated bleach asap.

Chlorine Date Code Decoder - Further Reading

www.troublefreepool.com

Follow this guide

How do I use Chlorine in my Spa or Hot Tub?

If you have a question about any information within this Sticky, please start a new thread for yourself where you will receive very quick responses to your specific questions. Thank you! Introduction There are two main things to consider when maintaining your hot tub water, Water Balance and...

www.troublefreepool.com

 

[Mdragger88]

OK, thanks. Will check out the PoolMath app. Is there a good online option for cheap liquid chlorine or does the water weight make it generally more cost-effective to buy from a local pool store?

Walmart, lowes, & Home Depot sell liquid chlorine for pools - some have been able to order it for delivery. You take your chances with freshness this way though as you can’t check the date before purchasing.

 

[Vesuvius]

Walmart, lowes, & Home Depot sell liquid chlorine for pools - some have been able to order it for delivery. You take your chances with freshness this way though as you can’t check the date before purchasing.

Great info--thanks much! I've been using Metal Magic after filling, as I don't filter the fresh water (not well water but just in case). Any concerns about this or other recommendations? Also, for Ahh-Some dosage purposes, if my spa holds max 525 gallons and I have it filled just below the pillows, what's a good estimate for the actual amount of water to be treated? I've never known if 525 literally means "filled up the top edge of the spa" or it means more "usable volume up to the pillows."

 

[Mdragger88]

For the Ahhsome I would just go with 4 tsp for the initial purge, then 1/2 that for each subsequent purge round (you don’t have to drain between them) until no more detritus is released then drain & rinse/wipe everything down.

Btw- If you use a drop based ph test you can fine tune your water volume in
PoolMath based on the results you achieve from your acid dosages. (Its best to use ph/acid for this because bleach strength can often vary from its listed percentage adding more variables but muriatic acid doesn’t really suffer from this issue)
My tub says 250gal but I use 200 for all my dosing & it comes out spot on.

 

[Methuselah]

It's probably in the sticky @Mdragger88 linked, but testing every 2 1/2 to 3 days probably won't cut it. At least not until your dosing becomes predictable.

Also, Metal Magic and other potions tend to cause more problems than they solve.

 

[Mdragger88]

If you don’t have signs of metals(iron) on the fixtures in your home (tub, toilet etc) then you can likely nix the metal magic. If metals present themselves once the tub is filled & adequate fc is present
FC/CYA Levels you can always add it if needed.

 

[Vesuvius]

For the Ahhsome I would just go with 4 tsp for the initial purge, then 1/2 that for each subsequent purge round (you don’t have to drain between them) until no more detritus is released then drain & rinse/wipe everything down.

Btw- If you use a drop based ph test you can fine tune your water volume in
PoolMath based on the results you achieve from your acid dosages. (Its best to use ph/acid for this because bleach strength can often vary from its listed percentage adding more variables but muriatic acid doesn’t really suffer from this issue)
My tub says 250gal but I use 200 for all my dosing & it comes out spot on.

Thanks again. This may be a dumb question, but how can you tell if no more detritus is released if there is a large amount of it from a previous round that was not drained out and cleaned up?

 

[Vesuvius]

It's probably in the sticky @Mdragger88 linked, but testing every 2 1/2 to 3 days probably won't cut it. At least not until your dosing becomes predictable.

Also, Metal Magic and other potions tend to cause more problems than they solve.

OK, thanks--will skip the MM and see how it goes.

Once I get things in balance and figure out how quickly things change, is it reasonable to think I can get back to a point where I just test and add chems once/week?

What do people do who go away on vacation for 1-2 weeks? I've used tri-chlor in a floating dispenser in the past but is there a better approach for someone using the dichlor/bleach method? Thanks!

 

[Vesuvius]

If you don’t have signs of metals(iron) on the fixtures in your home (tub, toilet etc) then you can likely nix the metal magic. If metals present themselves once the tub is filled & adequate fc is present
FC/CYA Levels you can always add it if needed.

Sounds good--thanks

 

[Methuselah]

OK, thanks--will skip the MM and see how it goes.

Once I get things in balance and figure out how quickly things change, is it reasonable to think I can get back to a point where I just test and add chems once/week?

What do people do who go away on vacation for 1-2 weeks? I've used tri-chlor in a floating dispenser in the past but is there a better approach for someone using the dichlor/bleach method? Thanks!

Absolutely! You can check/add once a month or once a year too if that's what you want. It's YOUR hot tub! Just curious, have you read through the links @Mdragger88 provided?

Trichlor desolves very quickly at hot tub temperatures...

Better approach, all kidding aside, maybe you would appreciate a salt water generator system?

 

[Bperry]

OK, thanks--will skip the MM and see how it goes.

Once I get things in balance and figure out how quickly things change, is it reasonable to think I can get back to a point where I just test and add chems once/week?

What do people do who go away on vacation for 1-2 weeks? I've used tri-chlor in a floating dispenser in the past but is there a better approach for someone using the dichlor/bleach method? Thanks!

Dichlor would be better than trichlor. Trichlor dissolves way too fast as high temp and when you’re away you want slow dissolving stuff. Vacation for 2 weeks would be better to shut it off, bring it to SLAM level, cover it and go on vacation. It should be fine when you get back if the temp is 70.

 

[Mdragger88]

A drape over swg (like the saltron mini or controlomatic) will handle the standby chlorination whether you’re home or not. Trichlor dissolves too rapidly in a hot tub & will raise fc & lower ph too much- this can damage surfaces & equipment like heater, cover & headrests.