Low Chlorine level

[shiyang100]

Tested water this morning with the test strip and found chlorine level is really low.

total hardness 250-500
Total chlorine 1
free chhlorie 0.5
ph 7.2
cyanuric acid 30-50
total alkalinity 80

My IC40 was setup at 40% with 9 hours pump run time. I changed it to 80% at 12 hours run time this morning. Should I shock the pool this evening? Do I need to turn off SWG while shocking the pool? Thanks.

 

[JVTrain]

Test strips are not sufficient for testing pool water and reliably maintaining sanitized water. You should have a recommended test kit such as the TF-100 from tftestkits.net or the Taylor K-2006. We can't really give you sound advice based on unreliable and inaccurate test strips.

 

[shiyang100]

Thanks Joel. Just bring the water to a pool shop. The numbers are right on spot.
Total chlorine 1
free chhlorie 0.5
ph 7.2
cyanuric acid 35

 

[pooldv]

OK, if, IF, you want to trust those numbers it is your pool. Here is what I would do with those numbers if I got them from my TF-100 test kit.

With FC at 1 it is very likely that you are growing some algae. First I would perform the Overnight Chlorine Loss Test to verify whether or not I have algae.
If I fail then I would SLAM my pool to kill the algae following this process, SLAM Process and then move on to below after I pass all three criteria of the SLAM.
If I pass then I would raise CYA up to 70 and chlorinate according to this, [FC/CYA][/FC/CYA] and balance my water according to this, Pool School - Water Balance for SWGs

Unfortunately, you can't do any of these things with Pool Store testing or with test strips. If you want to follow TFP then the first thing you must do is order a TF-100 from TFTestkits.net.

The chlorine level is set based on the CYA level and the [FC/CYA][/FC/CYA]. If FC drops below minimum then the pool is unsanitary, bacteria, viruses and pathogens are not killed quickly enough to prevent person to person disease transmission, especially in kids. And algae will grow. FC must be kept above minimum at all times for your pool to be sanitary and safe to swim. The first job of chlorine is to sanitize the pool, killing algae is just a side benefit.

 

[shiyang100]

My NEW TAYLOR K-2006 arrives today. Will submit another set of data tonight.

 

[pooldv]

Sweet!

 

[JVTrain]

You'll be much happier with your own test kit as it's more accurate and no time wasted running to the pool store. Post a full set of results with your kit once it shows up.

Do you have an approximate volume for your pool? Add that to your signature and you'll need it once your start dosing regularly and performing the SLAM, if needed.

Also, use a 10 mL volume for your FC/CC testing when you do the FAS-DPD test. 25 mL is not needed for most situations as 0.5 ppm resolution is enough. It saves a lot on reagents and something that often forgets to get mentioned when someone purchases a K-2006 rather than a TF-100.

 

[shiyang100]

Thanks Joel. Updated my signature...

 

[shiyang100]

Just did a few tests. Here is the result:
FC 5ppm
CC 0.5 ppm
Ph7.5
CYA 50

Will do the rest tomorrow. From the results so far, I assume it is ok.

But why the water is very slightly cloudy?

 

[pooldv]

Those numbers are good. If the FC spent some time below 4 ppm that is likely what caused the cloudy water. Raise FC up to 8 or 9 to see if it will clear up.

 

[shiyang100]

I repeated FC test this morning and the number dropped to 3. This fails overnight chlorine test. So I went ahead to shock the pool. Now I noticed my filter pressure went up from 15 to 17 in a matter of 2 hours. Is that something I need to worry about?

 

[domct203]

I repeated FC test this morning and the number dropped to 3. This fails overnight chlorine test. So I went ahead to shock the pool. Now I noticed my filter pressure went up from 15 to 17 in a matter of 2 hours. Is that something I need to worry about?

This would mean that the filter is catching the dead algae.

You said you shocked the pool. Are you following the SLAM Procedure, or are you using the pool $tore 'shock & pray' method?

Dom

 

[shiyang100]

Since I need to go to work today. I just use super shock it 73. Predissolved and slowly pour in front of return jet. I want to do SLAM this afternoon after back from work.

 

[domct203]

Since I need to go to work today. I just use super shock it 73. Predissolved and slowly pour in front of return jet. I want to do SLAM this afternoon after back from work.

Seems like extra work (with the dissolving) compared to liquid chlorine (aka bleach).

Also, that Super Shock It 73 is Cal-Hypo, and is adding to the CH (calcium) levels in your pool (something you have not yet posted a test result for).

A SLAM is not an 'afternoon thing', and you really need to stay on top of the FC levels, especially in the beginning of the SLAM.

Please post a complete set of current test results from your K-2006 for:
FC
CC
PH
TA
CH
CYA

Dom

 

[shiyang100]

Filter pressure is still climbing at slow rate. Now it sits at 17.3.

this is sta rite system 3 S7M120 filter. I was told it only needs to be cleaned once a season. In Massachusetts, this is about 3 months. Never thought it went up so quickly. It has been stable at around 14/15 since pool opening 3 weeks ago. The pool was basically green at that time. No pressure buildup at that time. I am afraid I did something wrong. New pool user gets worried easily.

 

[pooldv]

Cleaning once a season only applies to a clean pool. Algae quickly clogs a filter and with algae the filter often needs to be cleaned daily. Clean your filter when pressure rises 20-25% over clean pressure.

 

[shiyang100]

;Thanks so much. So I will star SLAM this week. Do I have to use algaecide at the same time?

 

[domct203]

;Thanks so much. So I will star SLAM this week. Do I have to use algaecide at the same time?

Algaecide is more of a preventive treatment, and is usually not needed in a properly sanitized pool.

Chlorine is your friend. Be sure to read up on the SLAM procedure if you haven't already.

http://www.troublefreepool.com/content/125-slam-shock-level-and-maintain-shockingl

Follow it to the letter and you will be rewarded with the clearest, sparkling water ever.

Be sure to post that complete set of test results to help everyone guide you, and post any questions you may have.

Dom

Edit:
When I say 'chlorine', I mean liquid chlorine, aka bleach. No more tablets or bags of shock. Good ol' laundry bleach is 8.25% sodium hypochlorite, the active ingredient in liquid chlorine. No splashless, sented, or otherwise special bleach, and avoid the dollar stores as their bleach has been know to be very low in concentration, and old.

Walmart's Great Value brand is a, um, a great value, as well as Clorox when on sale.

I go to Ocean State Job Lot and buy 1-gallon bottles of 12.5% liquid chlorine for $2.99 a bottle, which goes on sale for 4-gallons for $10 a few times a season.

Dom

 

[JRODinKC]

I recently joined TFP. Wow, great info everybody! I'm dealing with low FC as well. Newbie to the pool world. Test kit is on its way. Jerry

 

[shiyang100]

This would mean that the filter is catching the dead algae.

You said you shocked the pool. Are you following the SLAM Procedure, or are you using the pool $tore 'shock & pray' method?

Dom

just a follow up. Have been extremely busy for the past three days. Didn't get a chance to SLAM the pool. But what I found is the filter pressure goes up 1 psi per day. It is somewhere between 19 and 20 now. Is that something I should worry. My short experience with pool filter is they were quite stable at 14-15 until I shocked the pool on Tuesday. It just keep going up