Need help with my green pool!

[yeggim]

I have the FAS-DPD. I got the results when I multiplied the number of drops needed from the R-0871 reagent to change water from pink to colorless (43) with the drop equivalence found in step 1 which was 1 drop= 0.2 ppm. Sounds like I did it wrong

I ask because .86 in not a multiple of .2. Four drops would be .8 and five drops would be 1.0. 43 drops is 43x.2 which is 8.6. No big deal if .86 was a typo but could be troublesome if you're basing your bleach additions on .86 and not 8.6.

Anyways you don't need to test to the .2 accuracy on the FC test. Instead of using the 25 ml sample, use the 10 ml sample where each drop equals .5 It'll save your R-0871 reagent. The 25 ml sample uses 2.5 times the reagent to get your results. A .5 accuracy is good enough.

Are you planning to drain some and replace your water to reduce the CYA?

 

[Gfamily]

Ahh that's what I I'd wrong it's 8.6! Someone suggested I may have to drain the pool

 

[Gfamily]

Re: Would appreciate any help and assistance I can get

Sorry read my results wrong! My FC is 8.6 ppm

 

[techguy]

Ahh that's what I I'd wrong it's 8.6! Someone suggested I may have to drain the pool

Having a FC of 0.86 means it is very low...critically low if you are looking to prevent algae.

The dump and fill is to fix your CYA issue.

Have you run a complete set of tests on your pool water?

FC - Free Chlorine
CC - Combined Chlorine
pH -
TA - Total Alkalinity
CH - Calcium Hardness
CYA - Cyanuric Acid (stabilizer)

At this point, I feel your (accurate) CYA is the most critically needed piece of information.

 

[frogabog]

Re: Would appreciate any help and assistance I can get

It looks like you're using the 25ml sample to test chlorine. That's a little precise for our purposes here. You can go ahead and use the 10ml sample, and value each drop at .5ppm instead. It'll save your R-0871 reagent by half.

Looks to me like the only thing you really need to do right now is drain and refill 60% of the pool and stop using tablets/pucks/trichlor. From then on (assuming CYA is in the 40-60 range, 40-50 is better though) only use liquid chlorine (bleach at 6%, or pool store 12% liquid chlorine). Your plan of attack is to raise FC to the maximum for your CYA level in the evening after everyone is done swimming and the sun is off the pool so that the next day you're ready to lose ~50% of the chlorine. At end of the day, dose again in preparation for the next day. Pool Calculator (see my sig) is your friend for determining dosages.

The pH is low because you're using trichlor. When you switch to bleach, that will very likely creep up over time and need to be lowered occasionally. I wouldn't mess with it right now though. See what happens after you switch to bleach.

So, how does the water look? 8.6ppm is only .6ppm above minimum for 110ppm CYA. You're right on the edge of it being too low. Maintain that or higher until you lower CYA level and by all means, discontinue the pucks. Save them for vacations. They should last forever if stored properly.

 

[Gfamily]

Re: Would appreciate any help and assistance I can get

Thanks! Yesterday the water was green and cloudy today after adding some shock to the pool and letting the pump run for about 6 to 7 hours it's actually cleared up. is there any particular brand of liquid chlorine I should use

 

[Gfamily]

Sorry techguy! My FC is actually 8.6, I calculated wrong (rookie).

 

[duraleigh]

gfamily,

Do not run simultaneous threads on the same or similar subjects...it is very confusing to everyone.

Newbies....please do the same. Even if your 2nd question may seem unrelated to your first, please keep it in your first thread so people can see your whole story and you don't have to search the forum trying to find your posts.

 

[zea3]

Hi Gfamily, welcome to TFP! The pool is likely turning green due to the high CYA. If you do not have any water restrictions in your area you should drain about 50% of the water volume of the pool and refill with fresh water before you conduct the shock process. With 110ppm CYA your shock level would be 26ppm FC. That is a lot of bleach to reach and maintain that shock level. If you keep the CYA at 110ppm then your daily FC target is 8-14ppm. You would want to keep the FC at the top of the range and never allow the FC to drop below 8. In the long run it will be easier to shock and maintain the pool with a CYA of 50-60.