Post-Usage Dosing

[seb101]

I have a 1500L Jacuzzi 465 with a Clearray UV system, but no ozone generator.  While I am able to maintain good non-use bromine levels using my float dispenser, but post usage the spa is always dropping to 0 free bromine levels by the next morning.

Routinely there are only two of us using the spa, for an average of an hour.   I've been steadily increasing my post-usage dosing over time but it seems to never be enough.

Currently I'm dosing with 30g of non-chlorine oxy-shock and 30g of bromine after each use, which the manufacturer says should increase the levels by 3ppm - I would have thought this combined with the slow-release of the float dispenser would be enough to get back to normal level by the next morning, however this is not the case.

Do I need to just keep increasing the post-use bromine dose until it works (seems expensive!)?  Or is there something else I am doing wrong.  PH and TA tend to deviate low, but I routinely correct this, however our water is on the hard side (measures 1000 ppm) and I don't know if this needs to be fixed or is contributing to problems. 

Any advice appreciated!

 

[cranbiz]

Generally you want your hardness in the 200ppm range. I would get it down to 200ppm and then see what happens with keeping levels where they should be.

[CanadianSpaTech]

How old is the spa? When was the last time you did a plumbing purge? How often do you clean filters?

[seb101]

The spa is a 2012 J-465 model.  The plumbing was purged and the filters changed a couple of weeks ago.  The water is always perfectly clear, but just the bromine level never got above 1-2ppm.

I’ve now tracked this down to faulty test strips, after giving the tub a dose of bromine that should have sent it through the roof the strips were still reading 1-2ppm. Seems these strips just don’t work properly with bromine (despite stating it on the packaging).  I got some new strips and they are showing levels consistent with my dosing.  The faulty strips were also putting my water hardness at over 1000ppm whereas on the new strips it measures 200-300ppm where I expect it to be based on our local water company levels. 

The strange thing is… the faulty strips were recently purchased from a large reputable UK supplier… I won’t name them, but I won’t be buying from them again. 

Out of interest, how do others test their test strips?  Just keep a few from the last batch and make sure the new ones match?

[CanadianSpaTech]

Invest in a Taylor test kit

[cranbiz]

Don't use strips. They are hard to read and inaccurate. Like @CanadianSpaTechsaid, get a Taylor kit K-2106 for Bromine if you plan to stay with Bromine.

[Cusser]

Wow - I've had my CalSpa since 1988, and I've never done any Post-Usage Dosing.

I also use the OTO and phenol red dropwise test kits, I test maybe once every two weeks, use a bromine tablet floater in mine.

[seb101]

I think the total inaccuaracy of the test strips was causing me to massively over-dose the spa.  For the last few days I've stoped the bromine dosing after use and just given it the oxy-shock, along with the bromine float dispenser.  All seems fine now.

 

 

[CanadianSpaTech]

I only add NON chlorine shock every Sunday morning and only a cap (25g). I let the spa run for the day and then clean the filters later in the day. If the spa is cloudy then I will add 75g and let it run until it clears up and then clean filters. Cleaning the filters weekly.. bi-weekly at most. Do not wash swim trunks with regular laundry. Just rinse after each use. Bromine tablets are slow release so after a heavy bather load the residual level might drop so after each use depending on bather load or when I plan to use the spa again I might throw in a teaspoon of granular bromine to get the level back up quicker and then the tablets can maintain from there. If I am not going to use the spa for another day or 2 then the slow release tabs will have enough time to get the levels back up. Shock is used to control the organic contaminates (All the stuff you bring with you when you use the spa) and to get the particulate over to the filters. It brings the particulate together so they are combined and big enough for the filters to pick up. So again I only use a 25g cap full a couple of hours before cleaning the filters each week or 75g as required to clear a cloudy spa. Soak filters in a filter wash solution every 6 weeks to do a deeper cleaning for the body oils, hair and mucus that will accumulate in the crease of the pleated filters. Soak, rinse and dry. Always good to have a second set of filters. Use a plumbing line cleaner every 3 months before draining the spa to remove any organics from the lines that might be eating up your sanitizer. I use Ahh-Some products.

Keep your filters clean and everything else becomes easier. Don't over test. I test 1x per week unless I can visually see/smell a water quality issue. If it looks clean and clear and smells clean you are good to go. 

Less is best. You can always add a bit more but can't take it back out again.

[waterbear]

Read this:

https://www.poolspaforum.com/forum/index.php?/topic/53410-how-to-use-bromine-3-step-method/

On 6/17/2023 at 2:30 AM, seb101 said:

after giving the tub a dose of bromine that should have sent it through the roof the strips were still reading 1-2ppm. Seems these strips just don’t work properly witsorryh bromine (despite stating it on the packaging).

 

were the color blocks for these strips shads of pink and red? If so they are using DPD reagent and are bleaching out due to high bromine levels.

On 6/17/2023 at 2:30 AM, seb101 said:

 I got some new strips and they are showing levels consistent with my dosing.

Are the color blocks on these strips in the yellow/green range or blue/purple? Different testing reagents less prone to bleachout

 

On 6/17/2023 at 2:30 AM, seb101 said:

The faulty strips were also putting my water hardness at over 1000ppm whereas on the new strips it measures 200-300ppm

.Strips can only test total hardness (calcium + magnesium) but you are only interested in calcium hardness. No strip will give you useful info for balancing water. You need a different method of testing to do this. Also, as you have seen, the total hardness test is not very accurate (reporting the acutal value, not is it very precise (+/- 40 ppm, which is the usual range for strips, is usless for balancing water. You need +/- 10 ppm or better.

 

On 6/16/2023 at 6:02 AM, seb101 said:

PH and TA tend to deviate low, but I routinely correct this

You shouldn't have to,  Set your TA to 50-70 ppm. Sorry, strips don't have the precision to do this. You need a better testing method. Read this:

https://www.poolspaforum.com/forum/index.php?/topic/28846-lowering-total-alkalinity-howto/

 

On 6/17/2023 at 2:30 AM, seb101 said:

Out of interest, how do others test their test strips?

 I don't use strips. I used a drop based testing method that employs color matching and titrations. The Taylor Technologies kit that I use is not available in the UK to the best of my kowledge but there are good alternative from LaMotte and Hach.