1 Month in Question about Pool Test Results

[Breadbrian]

Ive been testing daily/weekly and noticed a discrepancy with the daily chlorine test vs the free chlorine test from my Taylor Kit. After 2 days of heavy rain my FC is 1.5 which i know is very low but my daily chlorine test (yellow) has a much higher reading. Ive also noticed black marks that reappear on the baja shelf after i brush it. It remains clean for 2 days and it begins to reappear. Could this be black algae? Mind you this is a brand new pool and salt was poured in a couple days ago by the builder but the Ichlor has not activated bc of cold temps. Thanks for all your advice TFP amigos!

Todays reading:
FC 1.5
PH 7.8
TA 110
CH 225
CYA 70

 

[PoolStored]

Ive been testing daily/weekly and noticed a discrepancy with the daily chlorine test vs the free chlorine test from my Taylor Kit. After 2 days of heavy rain my FC is 1.5 which i know is very low but my daily chlorine test (yellow) has a much higher reading. Ive also noticed black marks that reappear on the baja shelf after i brush it. It remains clean for 2 days and it begins to reappear. Could this be black algae? Mind you this is a brand new pool and salt was poured in a couple days ago by the builder but the Ichlor has not activated bc of cold temps. Thanks for all your advice TFP amigos!

Todays reading:
FC 1.5
PH 7.8
TA 110
CH 225
CYA 70

HEY!! First, trust your FAS-DPD test (the one with the powder). It is accurate (the most of any FC test you can reasonably run).

Second, I would get some Liquid Chlorine in that pool, post haste. I would get it into the range of 8-10 AND KEEP IT THERE DAILY WITH Liquid chlorine, and treat the pool as a liquid chlorine pool until the SWCG comes back on consistently.

Third, yes, it is possible that it is black algae. Let's get that FC up into the 8-10 range, then do an Overnight Chlorine Loss Test. Link-->Overnight Chlorine Loss Test

 

[Breadbrian]

I should add theres a bunch of worms that ended up in the pool overnight due to the rains. Would this affect the FC levels?

 

[Breadbrian]

HEY!! First, trust your FAS-DPD test (the one with the powder). It is accurate (the most of any FC test you can reasonably run).

Second, I would get some Liquid Chlorine in that pool, post haste. I would get it into the range of 8-10 AND KEEP IT THERE DAILY WITH Liquid chlorine, and treat the pool as a liquid chlorine pool until the SWCG comes back on consistently.

Third, yes, it is possible that it is black algae. Let's get that FC up into the 8-10 range, then do an Overnight Chlorine Loss Test. Link-->Overnight Chlorine Loss Test

Thanks PoolStored! Knowing there will be more rains in the upcoming days do i wait for clear weather before treating? Or do you suggest I proceed with addressing the water as levels drop.

 

[PoolStored]

I should add theres a bunch of worms that ended up in the pool overnight due to the rains. Would this affect the FC levels?

Yeah, not much, just get them out. Skimmer net, robot, whatever.

Thanks PoolStored! Knowing there will be more rains in the upcoming days do i wait for clear weather before treating? Or do you suggest I proceed with addressing the water as levels drop.

No, get your FC up NOW. Tonight if you can. The faster you get in front of this the better. 1" of rain in a 20x40 pool is 500 gallons out of 30K. About 1.6%. Ignore the rains, get the LC into the pool and keep your FC up 9-10 daily. With a CYA of 70 and FC 1.5, you are sitting duck for algae.....Read this-->FC/CYA Levels

Maybe, revisit this too-->Pool Care Basics

 

[HermanTX]

The FAS=DPD test (powder) measures FC and is the most accurate.
The daily test - which I assume is just drops in a color comparator measures TC (Total chlorine).
TC = FC + CC So it makes sense that the TC is higher than FC in your tests. The CC implies algae or some other organics are eating the chlorine. Remember that we look for CC to be 0.5 or less.
Did you do a CC test after the FAS-DPD test? What was that value?
Suggest you use liquid chlorine to raise FC asap.

 

[Breadbrian]

@HermanTX i just poured a gallon of KemTek liquid chlorine but unsure how to log this in for the the app. Is this the same as 6% bleach?

 

[Breadbrian]

@HermanTX i just poured a gallon of KemTek liquid chlorine but unsure how to log this in for the the app. Is this the same as 6% bleach?

Im realizing the kemtek is 10% based on the label stating sodium hyporchrlorite

 

[PoolStored]

Im realizing the kemtek is 10% based on the label stating sodium hyporchrlorite

Log it as 128 ounces, 10% Bleach. or 1 Gallon, 10%. Should raise your FC by 9.6. Make sure you pour it in over a return. Should take 2 minutes to pour the gallon in a pencil thin stream.

Make sure pump is running. You can retest after about an hour to see if you got expected results, make sure pump is running.

 

[PoolStored]

If you test FC again, after 1 hour and after sundown, you can do OCLT tonight. Use the result as your starting FC. Get up before sunrise and test again. If FC loss > 1, then time for a Slam.

Overnight Chlorine Loss Test
SLAM Process

If you end up doing a SLAM to kill algae, we will help you with black algae cleanup.

 

[Breadbrian]

If you test FC again, after 1 hour and after sundown, you can do OCLT tonight. Use the result as your starting FC. Get up before sunrise and test again. If FC loss > 1, then time for a Slam.

Overnight Chlorine Loss Test
SLAM Process

If you end up doing a SLAM to kill algae, we will help you with black algae cleanup.

Tested and current FC is 13.5. Ill report back first thing in the morning. Appreciate your help PoolStored. Hope to pay it forward one day.

 

[Breadbrian]

Good Morning, tested and new FC results are 10. Loss of 3.5 which means i should SLAM. Ill follow the youtube video process in the SLAM link. Should i be getting my PH down to 7.2 before starting this process or is my current 7.8 enough? Thanks

 

[HermanTX]

Good Morning, tested and new FC results are 10. Loss of 3.5 which means i should SLAM. Ill follow the youtube video process in the SLAM link. Should i be getting my PH down to 7.2 before starting this process or is my current 7.8 enough? Thanks

It is prudent to lower your pH before a SLAM because testing of pH during a SLAM (which has elevated FC levels) is inconsistent. It doesn't need to be exactly 7.2 but if your water tends to raise pH quickly it is best to lower the pH somewhat then commence the SLAM. Good luck and keep us posted.

 

[PoolStored]

Ill follow the youtube video process in the SLAM link

I found that printing out the instructions and having them with me to read really helped. Read it three times. The more often you can replace FC the better (test and replace every 1-2 hours). Scrub, scrub, scrub everything. If you have removable lights, remove and scrub behind them, scrub the skimmers, take out the weir doors and scrub them, check the foam for algae in the weir doors, if so, soak/scrub them a bit in 10:1 water:bleach solution (or replace the foam is really bad). If you have a ladder take it out and scrub inside the tubes. Can you post a picture of the pool and water? What was your CC when you tested?

 

[PoolStored]

Could this be black algae?

Do you have a stainless steel brush. Probably should get one. While you are slamming, scrub the areas that were black with the SS brush several times a day.

LINK-->

Amazon.com : Stainless Steel Pool Brush

 

[Breadbrian]

@PoolStored Ive attatched a photo of the black spots on the baja shelf. For now its pretty isolated and the size of a quarter and when left alone can get as big as 2 inches. Ive been scrubbing with the pool nylon brush. Outside of that i dont see any black spots. Ive noticed some discoloration on the pebble fina but thought that was mottling as its been there for some time. Perhaps algae? Photo attatched as well.

One other question, I noticed when i add more liquid chloring the ph goes up and it requires me to add more acid does this sound right to you?

 

[Breadbrian]

It is prudent to lower your pH before a SLAM because testing of pH during a SLAM (which has elevated FC levels) is inconsistent. It doesn't need to be exactly 7.2 but if your water tends to raise pH quickly it is best to lower the pH somewhat then commence the SLAM. Good luck and keep us posted.

@HermanTX I added muriatic acid and noticed the ph levels still went up. Is this bc of the liquid chlorine?

 

[PoolStored]

@PoolStored Ive attatched a photo of the black spots on the baja shelf. For now its pretty isolated and the size of a quarter and when left alone can get as big as 2 inches. Ive been scrubbing with the pool nylon brush. Outside of that i dont see any black spots. Ive noticed some discoloration on the pebble fina but thought that was mottling as its been there for some time. Perhaps algae? Photo attatched as well.

One other question, I noticed when i add more liquid chloring the ph goes up and it requires me to add more acid does this sound right to you?

Re-read SLAM process again. You lower pH with Muriatic to about 7.2 ONCE before SLAM. During slam don't add any more acid! ONLY Liquid Chlorine. You are probably ok, don't add more acid.

Can you get some of the black in your fingernail and wipe on a paper towel? If black algae, it will smear a dark green.

 

[PoolStored]

Is this bc of the liquid chlorine?

Has to do more with the test. The pH test is only valid with FC below 10.

 

[HermanTX]

@HermanTX I added muriatic acid and noticed the ph levels still went up. Is this bc of the liquid chlorine?

Liquid Chlorine does not increase pH. As indicated earlier, do not test pH with elevated FC levels (above 10). If you need to lower pH, do it before you add LC to increase FC to SLAM level.

Also, you should wait a minimum of 30 minutes before testing after you add any chemical and this assumes you have the pump circulating the water.