Yellowtrine

[mark m]

I added 12 oz of yellowtrine to my 27000 gal pool to get rid of mustard algae. A week later still no chlorine readings and ive added 10 pounds of Cal Hypo granular chlorine. Pool store tells me i need to keep adding till i break the bearier. Is this correct? ph is good, well just a little low 7.0. alkalinity is good cya is good calcium is good. is it ok to swim? and do i keep adding chlorine? pool is clear right now.

[Watermom]

I've asked PoolDoc to reply to your thread as he is more familiar with handling a pool where Yellowtrine has been added. Sit tight.

By the way, pH below 7.0 is not good. Readings below 7.0 are acidic and can damage your pool and equipment.

What kind of test kit do you have? He is going to want some current numbers to look at and not just that things are 'good.' (Test strips don't count --- we call them guess strips.)

Welcome to the Pool Forum.

[mark m]

I have the big taylor test kit the ph is at 7.0 only been that low for couple of days. everything else is good

[chem geek]

Yellowtrine is 98% sodium bromide so 12 ounces of it in 27,000 gallons is 3.3 mg/L of sodium bromide or 5.2 ppm bromine (equivalent to 2.3 ppm chlorine). Adding chlorine to your pool should result in readings regardless of whether chlorine or bromine is produced.

I assume you realize the chlorine or bromine is consumed EVERY DAY not only by algae but also by sunlight as well as oxidizing other things in your pool. So if you added 10 pounds of Cal-Hypo, let's say 65% Cal-Hypo, to 27,000 gallons then that is 28.6 ppm FC which if you had algae in the pool might not last a week. You should test the chlorine level about an hour after adding it assuming your pump is on and you have decent circulation.

Also, if you are using a DPD chlorine test that is shades of pink/red, then that bleaches out at high chlorine levels. This is why we recommend the FAS-DPD chlorine test in the Taylor K-2006. What do you have? Do you have the K-2005? That has the DPD test that bleaches out at high chlorine levels.

[PoolDoc]

You can go to Walmart, and get a cheap OTO/phenol red kit. OTO is not super accurate, but it is super reliable: if you get a ZERO reading with OTO, you have zero chlorine. If the chlorine is 10, 20, 40, or even 80 . . . you will still get a positive result with indication of the level, as the OTO gradually goes from yellow to orange and finally brown.

If you get a zero reading with DPD color matching . . . you might have zero FC and high CC or you might have high FC, or you might actually have zero chlorine.

The K2006 overcomes this problem, and allows accurate measurements up to around 40 - 50 ppm, and fairly accurate distinction of FC vs CC, where OTO only gives a crude and tricky distinction and tends to only give TC (FC + CC) results.

Also, it may not be clear from Chem_Geek's post, but YellowTrine (sodium bromide) turns your stabilized chlorine pool into an unstabilized bromine pool, which can lose ALL of its chlorine or bromine in a couple of hours.