CYA test accuracy and algae

[mikefamig]

It's been made clear to me from posts here that I'm not the only one that has trouble determining the results of the CYA turbidity test. Being that preventing algae growth is to a great deal dependent on FC level and your FC level is based on the CYA level, this is a critical fault with the BBB system.

Here is my point - Last year I had trouble with alage when maintaining 6 - 8 ppm FC at 50 ppm cya in accordance with the chart. This year I still read the cya to be 50 ppm but I am maintaining about 8 - 10 ppm FC and no algae. I understand that 7.5 % of cya or ~ 4 ppm on the chart is supposed to be high enough to kill algae and bacteria at 50 ppm cya but that hasn't been my experience. The problem is that I don't want to constantly over-chlorinate and I have no way to know if I am using more chlorine than necessary. The only way that I know to tell if my FC is too low is to lower it until I grow algae. There is no way to tell if it is too high.

My question - is there any health concern with keeping FC at 10 ppm with CYA at 50 ppm? How critical are these numbers? It occurs to me that it may be healthier for the swimmer to maintain slightly lower FC levels and deal with a little algae than to over-chlorinate.

Mike.

 

[Catanzaro]

Mike:

It is safe to swim up to SLAM level. A couple things come to mind:

1) How long are you running your pump?
2) How many returns in the pool?
3) Do you have a main drain?
4) Do you have one or two skimmers?

I am a big believer in circulation in a pool. More water movement, less problems. Maybe there are some dead spots that contribute to algae growth and you keep nipping it in the >>>>. How often did you brush your floor and walls with the lower levels? Even at these levels you are 17%-20% of CYA, which is high for a pool. Let's investigate a little bit and we can go from here. I only have to keep these type of levels in my pool when using a solar cover for an extended period of time. Also, I have been able to cut back to my normal levels without any problems by removing the cover early morning.

Are you using a solar cover as well? Please provide some more detail. Thank you.

 

[cfherrman]

No thoughts should be given about FC up to 40% cya. If your poop is troublesome some people use the next 10 on the cya/FC chart untill they find the source of the problem

 

[mikefamig]

You saved the best for last......the solar cover. Last year the pool was covered most of the time. My wife is the only one that swims for the most part and only a few times a week. We were in the habit of putting the blanket on each evening and at times it didn't come off for days. But why does the cover promote algae growth?

The circulation isn't great but it is what it is. I have output ports that I point at the still spots as much as i can.

The pump runs 12 hours/day because I was getting algae when I ran it 8hrs/day.
There four returns. One located near each end of the long wall and two in the stair-case
No main drain
One skimmer

Mike.

 

[Catanzaro]

The pump runs 12 hours/day because I was getting algae when I ran it 8hrs/day. There four returns. One located near each end of the long wall and two in the stair-case. No main drain One skimmer

Water on the surface is slowed tremendously and that could be your problem. I just had a similar issue, but now the cover only goes on at night (by 8 p.m. the earliest) and off by 8 a.m., the latest. I save 2 degrees from loss, and now no algae problems.

 

[Pwareing]

I find the nature and sentiment of this posts fascinating - we are told to bin the 'guess' test strips and invest in expensive testing reagents that have dodgy or wildly varying results at best - but isn't that the charge levelled at the test strips?.
I have been a paint technologist in the liquid testing and colour testing industry for 30 years and some of the quoted accuracy levels are frightening. To be honest that is part of the reason I am holding off investing, the other of course is the rip off price (175$) over here!
I just feel like I need proof/assurance that the kits are going to provide reliable repeatable results.

 

[cfherrman]

Strips will just go inaccurate, meaning they read all over the place

Strips also just give numbers, 30-50 cya, well is it 30, 40, 50? Skip 50-70 and head over 70.

Strips also don't go over 5 fc

Strips just don't work, so many people have run in circles because of it.

 

[Pwareing]

I understand what you are saying but I think I read CYA accuracy of +/- 15ppm as being good on the turbidity test so CYA strip reading 30-50 doesn't sound that bad. It seems CYA is the all important reading so it is important to get accuracy surely?
FC can be tested with dilutions.

 

[cfherrman]

I believe it's +/-10, bit still, strips don't read 60 or 70 and they also don't read accurate or will just fall out

 

[Catanzaro]

I find the nature and sentiment of this posts fascinating - we are told to bin the 'guess' test strips and invest in expensive testing reagents that have dodgy or wildly varying results at best - but isn't that the charge levelled at the test strips?.
I have been a paint technologist in the liquid testing and colour testing industry for 30 years and some of the quoted accuracy levels are frightening. To be honest that is part of the reason I am holding off investing, the other of course is the rip off price (175$) over here!
I just feel like I need proof/assurance that the kits are going to provide reliable repeatable results.

Please explain a little more in detail? How much do test kits cost in France, and do you use any method. The TF-100 is consistent regarding testing.

 

[ajw22]

What exactly are you referring to? Your post is confusing and test kits do not cost $175 and no where close. There are hundreds, if not thousands of members who own the recommended test kits that have never complained that they cost too much. Please explain yourself.

Note the Pwareing is in France. Prices are different in other countries.

 

[Catanzaro]

Note the Pwareing is in France. Prices are different in other countries.

Thanks as I edited my post. Although, the location should be not labeled to reflect an e-mail.

 

[ajw22]

Thanks as I edited my post. Although, the location should be not labeled to reflect an e-mail.

Language translation and cultural differences. Physical location or cyber location?

 

[Pwareing]

Hi there sorry for slow response - time zone differences. The Taylor K2006 (not even the K2006C) costs 175$ delivered. I have not got a price for the TF100 not sure if it is even possible - perhaps Dave can enlighten me?
Currently I use OTO/PH drop test with dilutions and back it up with Aquachek 7 on the same dilutions. I also do daily rough sampling with the OTO using the 'vivid yellow', 'light orange', 'dark orange' and 'brown' to keep my FC in daily shape.
I know the OTO/PH drop test is not accurate an gives ranges using the colours mentioned but if I go near anywhere near yellow I know its time to add/double check with dilutions.
I do what I can but I am a convert to TFP and am just waiting for a upturn in finances- by the way the OTO/PH kits are slightly smaller collectors here (4 drops of reagent) and are 2$ for refills.

 

[Pwareing]

I have updated the location - sorry about that I never completed that part and it must automatically filled this with gmail?

 

[Catanzaro]

I have updated the location - sorry about that I never completed that part and it must automatically filled this with gmail?

Given your situation, it may be best to assume 10-20 ppm higher on the CYA and run the pool at slightly higher chlorine levels for a while. If the pool seems fine, then you can slowly and gradually decrease the levels, but I do understand your frustration. Without a quality cost effective kit, things do not always go smoothly. Off the subject, I was in Italy and near France in 2011, 2013, & 2016. Heading back next year.

 

[mknauss]

Here is some information on obtaining test kits in your area.

How to Buy a K2006 or K2006C Outside the USA:
Spain & Portugal: only BEHQ SL (34-93-846-53-36) or [email protected].
Rest of the World: pretty much only HornerXpress Worldwide in Fort Lauderdale, Florida (954-938-5355) or [email protected].

How to Buy LaMotte 7002 FAS-DPD Commercial Series Kits (FAS-DPD Commercial 7 Kit):
UK: poolandspacentre.co.uk or sword-scientific.com or pro-swim.co.uk

How to Buy Palintest: [SP 315C (similar to K-2005) AND/+ SP 300 FAS-DPD chlorine test]
UK: Tel: +44 (0) 191 491 0808 ext. 208 Email: [email protected] or camlabworld.com or pool-chem.co.uk

How to Buy Lovibond test kit:
UK: pro-swim.co.uk or lovibondwater.com or leisureteq.co.uk

 

[Catanzaro]

To Marty for this valuable information. Great resources!