Kit vs Strips and Test Frequency

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K

Krooz

0
Mar 30, 2015
18
Moncks Corner
I've been a hot tub owner for 2 months and have been struggling with maintaining my Bromine at acceptable levels - based on test strips. I've learned a lot from this site regarding water chemistry (e.g. I had not been using any MPS nor bleach after a soak).

So, yesterday I tried something different. Before I got in the tub I tested it and the Bromine read 2 on the strip. After a 20 minute soak I added 1oz of 8.25% bleach - read it later in the day and the strip indicated the Bromine at 5 ppm - sweet! This morning I decided to compare the strip vs the Taylor kit. The strip indicated 0-1 Bromine - baah! Tested it with the kit and it indicated 4 ppm - that's more like it.

Anyway, the kit proved itself more accurate than the strips (as it should) and leads me to the following question....

- I did a test Monday with the new kit (didn't check Bromine) and got a Saturation reading of 0.2 on the Taylor Watergram. So, going forward, if I toss in a shot of beach after every use how often should I be testing the water? I'd like to think that I could just do a once a week check with the kit and not worry about using the strips every day like I have been doing. My ph kept getting on the low side too but I had been using MPS periodically to try to keep the Bromine up (based on strips) and now I understand that MPS tends to lower the ph.

Any advice is appreciated!

Thanks
 
I maintain my tub with 8.25% bleach. We use it pretty much every day. Through some trial and error and I arrived at about 1/4 cup bleach per hour or so of use. The most useful thing I have found besides TFP and Poolmath is a paper and pencil. Add what poolmath says and test it and then test the next day for residual and write it all down. Record this data for a few weeks and you will see a pattern of how much bleach adds immediately and how your residual ends up. if you are an every other day tubber you will need to add a little more today so you don't have to add any tomorrow and will have enough residual the next day when you want to get in.

I mostly test weekly now, occasionally more often if usage patterns are a little different. Or for a sanity check.
 
Been doing pretty well keeping the spa clear as a bell other than one blip where I didn't use (or treat) for a few days and the water clouded up a bit). Anyway, I used the tub Thursday morning and tossed in an oz of 8.25 beach. Wife had been out of town until Friday and we were going to use this morning - so last night I put in 2 oz of MPS just to prep for a.m. use. This morning I tested BR with strip and it read 2 - 5 ppm so figured we were good.

We went ahead and used it for an hour. I did my weekly test later with the Taylor kit and the Br was actually 12-13ppm -wow! So my question - are there any test strips that are reasonably accurate for spot testing Bromine between kit checks? The ones I have are 5 way by Sparco. They're pretty accurate regarding ph, TA but not even in the ball park for Bromine apparently.... ( I didn't add any bleach after use since the BR count was so high to start with)

Thanks
 
Test strips are very hit and miss depending on what they are measuring and the manufacturer/model of kit. For chlorine and bromine tests, most have trouble measuring high levels accurately, where some even have trouble above 5 ppm FC which is 11.25 Total Bromine. Some do OK up to 10 ppm FC which is 22.5 Total Bromine, but apparently this is not the case with the test strips you used.

pH tends to be the easiest test to get right on strips though even there they vary where at higher chlorine or bromine levels the results vary, and that's true even for drop-based liquid test kits. For pH one needs to have a special set of chlorine neutralizers so that the phenol red dye does not react with chlorine to give a falsely high pH reading. TA is only measured on a very broad range and CH isn't generally measured at all (it's usually Total Hardness that is measured). You can see in this post I wrote why test strips don't give you the accuracy nor precision needed, especially for calculating a reasonable calcite saturation index. That's not of concern in spas unless the pH, TA or CH are high in which case calcium carbonate scaling is of concern.
 
Thanks cg. I was trying not to burn up the components of the test kit too quickly but I guess I'll need to initially to get comfortable with what does what to the tub. I've been keeping a log like pooldv suggested, though not daily. Guess I need to bite the bullet and daily kit test the Br levels to get my understanding where it needs to be.

One more question. I was not advised by my PS to establish a bromide bank on my initial fill. Will doing that on my next fill help the Frog floater maintain a steady Br level? (do the levels ever stay steady or does it always fluctuate based on waste levels?)
 
pooldv said:
The most useful thing I have found besides TFP and Poolmath is a paper and pencil. Add what poolmath says and test it and then test the next day for residual and write it all down. Record this data for a few weeks and you will see a pattern of how much bleach adds immediately and how your residual ends up.
Click to expand...
This is a very important point that is often overlooked. Those who take the time to do this will be rewarded. After several days of testing and recording results on a daily basis to establish an initial baseline, I would suggest recording at least one test result a week for an entire year (or season if you winterize your pool). You can use paper & pencil or my tool of choice, Excel. I would also record the water temperature as part of your testing regimen.
 
Well, I've been testing my spa with the kit for 2 weeks now - daily if I don't use it and twice daily if I/we do. Adding 1 oz of 8.25% bleach (for 1/2 man hour use) appears to kick the BR up about 4 ppm and 2 oz raises it around 8 ppm. I do the full test once a week with only minor tweaks to the ph and TA and have been happy with the CSI calcs (0.04 this morning). I did add 3 oz MPS at one point and it got pretty "hot" (Br > 15 ppm) for about 16 hours.

From what I've been reading I think I can skip the dosing with the MPS, skip the daily testing and dose with the 8.25%C based on man hour use. I'll still do the full kit test once a week. I think this seem reasonable - yes/no?

Thanks!
 

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Thanks pooldv, I have seen those. I'm getting a pretty good handle on the next day residuals but I may keep the tight testing for another week. It's pretty interesting to see the differences in residual depending on bather load or lack there of.

I'm not really impressed with the Frog floater and it's ability to maintain bromine levels, it's like I have a 3-step setup but still have to tend to it like a 2-step system. I may forgo that when I do my water change out. Speaking of which, it is due now but the water seems fine and I may roll on another month or 2 or 3......
 
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