Another go at BioActive cyanuric acid reduction

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BenWilder

0
Jun 12, 2015
7
Tucson, Arizona
Hi Everyone,

I have read through many of the CYA posts on this topic. I understand generally poor results have been obtained. I am going to try this with FC = 0.

Quick background. I am a recovering dichlor abuser of 7 years. Thanks to this site, I, for the first time, feel like I understand how to maintain my pool properly.

I expected my CYA to be astronomically high. Using a 2:1 dilution (multiplying the result by 3) I came up with a CYA reading of 180 - 240. The discrepancy between the readings depended on whether I held the tube with the black dot in my shadow or in the sun. I know the shadow is preferred, but I had a much easier time judging when the dot disappeared with the sun illuminating the tube. That is, the results were more consistently repeatable. For this test, I will take CYA measurements the same way each time with the sun illuminating the tube.

Current water conditions:

FC = 4
CC = 0
pH = 8
TA = 100
CH = 450
CYA = 180
Temp = 83 F
Clear to sparkling

I added 2 cups of 200 Baume acid to bring the pH down to 7.5. Which I find I need to do about every week.

I had a slight brush with algae last weekend. Brushing, vacuuming, bleaching, cleaning the filter, etc. cleaned it up. There has been no CC for the last 4 days.

So, as I said, I want to try this Bioactive CYA reduction test with the FC close to 0. Should take about 3 days for my chlorine level to get there.

Let's see what happens...
 
Welcome to TFP! :wave:

You could dechlorinate more quickly which hopefully will help to prevent an algae bloom. You can do this by adding 10 cups of 3% hydrogen peroxide to the 10,000 gallon pool since that will eliminate 4 ppm FC of chlorine (be on the safe side and add a little less, then remeasure chlorine). I'd also lower the pH a little more to 7.4 or slightly below though the removal of chlorine will be a little acidic (i.e. pH may drop a little).
 
Thank you. And thank you for the hydrogen peroxide information. That would be smart to de-chlorinate more quickly. I am just reading this Sunday morning so that trick might have to wait until I can get some H2O2 and if the level doesn't reach zero before then.

Interestingly, after reading FC = 4 on Friday morning, FC was 1.5 yesterday and 1.8 this morning. I used the 10 ml sample yesterday and the 25 ml sample today. I was surprised that the FC level had not dropped more. Does de-chlorination taper off as it approaches 0?


You are right about pH. According to the bag of Bioactive CYA reducer I picked up at the pool store yesterday, pH 7.2 - 7.5 is preferred. Also according to the bag, it is suitable for treating any level of CYA, though it might take more applications at levels above 200. I think I recall in a different thread on this topic that a poster mentioned it is only useful for levels under 150.

I had the pool store measure my water. They found CYA = 110. I have since sampled my water twice both times coming in around 180.

The pool store also measured my phosphates at 300 ppb and recommended I use their Perfect Weekly phosphate reducer chemical. If I do that, that will happen after this CYA reduction experiment.

The $50 bag of CYA reducer is awfully small and expensive. I am not feeling very optimistic...
 
Yes, the usage/consumption of chlorine is a proportional (percentage) drop because the reaction rate slows down as the concentration gets lower. Your 1.5 to 1.8 doesn't sound right and may be where you are sampling if the water wasn't well mixed or may have been testing error. Let's say, however, that the drop is 50% per day. Then 4 ppm FC would go to 2 ppm FC would go to 1 ppm FC would go to 0.5 ppm FC, etc. Now if algae started to grow, then the loss would increase since there would be more for chlorine to oxidize so when that happens the FC would drop to zero more quickly.

You should not need to worry about the phosphates at all. Save your money on that. 300 ppb is pretty low anyway, but it's irrelevant since a sufficient FC/CYA level (see Chlorine / CYA Chart) will prevent green and black algae growth regardless of phosphate level.

Keep us posted. Yes, it's expensive so if we can't figure out how to make this thing work, we won't be recommending it. So far, it hasn't looked good with all but a couple of reports being negative.
 
chem geek said:
Your 1.5 to 1.8 doesn't sound right and may be where you are sampling if the water wasn't well mixed or may have been testing error.
Click to expand...

You are right about the sampling error. I took the 1.5 reading several hours later in the day and an hour or so after the pump had stopped compared to the previous day's 1.8 reading.

So, the de-chlorination went like this:

Friday morning FC = 4
Saturday morning FC = not sure
Sunday morning FC = 1.8
Sunday evening (6 PM) FC = 1.2

Then I started to get nervous about algae. I did not apply the H2O2 to remove all the chlorine. I applied the CYA reducer last evening (6 PM) following the instructions on the pouch. So much for the FC = 0 test, but hopefully, FC = 1.2 with CYA = 180 is weak enough not to harm the bacteria. Also, I do not plan to add any additional chlorine during the test.

Any reason to test for calcium hardness during this test?

Start of test water conditions:
Clear
Temp = 87 F (Bio-Active range: 65 - 105)
FC = 1.2 (Bio-Active range <5, 2 - 3 "ideal")
CC = 0
pH = 7.4 (Bio-Active range 7.2 - 7.6)
TA = 90
CYA = 180 (from Sunday morning's reading)


Day .5 (this morning) water conditions:
Clear
Temp = 84 F
FC = 1.0
CC = 0
pH = 7.6 (using Taylor acid demand test added 3 cups acid to bring pH down to around 7.3 -- checking the TFPC just now I see it calculates 12 oz. Yikes, did I look at the wrong Taylor chart?)
TA = 90
CYA = 120

Too soon to get excited. The CYA test is tricky for me, I am inexperienced, and I want this product to work so I am probably biasing the result.

Let's see what it looks like tomorrow...
 
I don't see where CH would be relevant. Phosphates might be since the bacteria may need some for their metabolism, but the CH shouldn't matter.

To go from 7.6 to 7.3 with your numbers would be 20-25 fluid ounces of full-strength Muriatic Acid depending on your actual CYA level. So that's around the 3 cups your acid demand test said.

The reason that PoolMath told you 12 fluid ounces is that it does not properly account for CYA in doing the calculation -- it only looks at TA (and Borates) and ignores the CYA. CYA is also a pH buffer. So you did the acid demand test correctly and should add around 3 cups of acid. My spreadsheet does the calculations correctly, but pH calculations are the most complex so PoolMath only does some of it correctly.
 
Day 1.5 Water Conditions:

Clear (Is it starting to look slightly less clear? Took a few swipes with the brush and didn't see any plumes of algae.)
Temp = 85 F
FC = .2 (Tap water read .2 this morning)
CC = 0
pH = 7.4 (added approx. 6 oz. acid (per Taylor acid demand chart) to keep pH in the low end of the Bio-Active "ideal" range 7.2 - 7.6)
TA = 80
CYA = 120

With optimism I used a 1:1 dilution factor (results X 2) to measure CYA this morning. Result same as yesterday. Is this the end of the CYA reduction? Should I double-down while my FC is low and try another (p)ouch?
 
This is about the same thing we are seeing over and over. Enough so now, that I'm getting convinced we had our hopes too high for this. Personally, I would save the money for refill and other things you may need for the pool. It's too bad, but I think they have a ways to go if this product is ever going to become something we can recommend. It's very disappointing, but sadly I think we can lower any hopes at this point.
 
Day 2.5 water conditions:

Water no longer clear. Milky is how I would describe it. Slightly milky.
Temp = 86 F
FC = 0
CC = don't know, forgot to measure
pH = 7.4 (added 6 oz. acid)
TA = 80, though very close to turning red at 70
CYA = don't know, ran out of reagent (more on the way)

I have never noticed my pool to have a "milky" look to it. Kind of looks like the CYA test mix, though not that cloudy. What does it mean?
 

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Usually that means there is algae growth starting. The BioActive people claimed algae would be suppressed while their product was being used though I don't know why that would be (they claimed something about competing for nutrients, but a pool rich in nutrients could probably support both the bacterial and algae growth). It's possible that if enough bacteria have grown/reproduced that they themselves are causing the cloudiness, but then I'd expect the CYA to be dropping if that were the case (assuming the bacteria do what they are supposed to).
 
Day 3.5 water conditions
Milky
Temp = 86 F
FC = 0
CC = 0
pH = 7.4
TA = 80
CYA = Unknown (more test reagent tomorrow)

Pool is cloudier, milkier than yesterday. Drains at 5 foot depth are partially obscured. Doesn't look like algae to me, but I am no algae expert.
 
You probably don't want it to go too long. If you've used up all the Bio-Active, then test the CYA tomorrow and then do a SLAM to kill off what is likely to be algae starting to grow. Algae can start out having the water look dull and then cloudy before turning green after clumping enough. Even if it wasn't algae and was bacteria, you'd want to kill that off anyway. Let's see what the CYA says tomorrow. I wouldn't go any longer than that and if you had the CYA reagent today I'd have you measure today and be done with this. The CYA reading tomorrow might be negatively impacted by the cloudiness, but it's still worth getting a reading both before and after the SLAM.
 
I was at the pool store this weekend and saw a bag of stuff that is supposed to lower the CYA levels. I searched this site and found this discussion. It is like reading a great book and finding out the last chapter had been ripped out. I wanted to know how this ended. :(
 
We have not had any consistent reports of this product working. Only sporadic reports on it kind of working, sort of, etc.

We do not recommend this product as it is a waste of money. Simply drain and refill if you can.


Sent from my iPhone using Tapatalk
 
It didn't do much for me...it reduced cya about 40 ppm (from 300+) but that could have been the error with dilution, but it was consistent.

and the part where they say it should help keep algae at bay is worthless...I had a mustard algae out break right after trying bio-active last year.
 
JoyfulNoise said:
We have not had any consistent reports of this product working. Only sporadic reports on it kind of working, sort of, etc.

We do not recommend this product as it is a waste of money. Simply drain and refill if you can.


Sent from my iPhone using Tapatalk
Click to expand...
I have a bag but am not using it due to reviews and negative press. I'm dealing with high CYA the old fashioned way. Replace water when feasible and use lots of bleach.
 

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