Algae and high CYA Help

[vans4]

Hello community,

I have a huge problem with my pool. It is green and the chemistry is way off. I had an extended hospital stay and now I am faced with getting the pool back to a balanced state. I had my wife using pucks while I was away.

Particulars:
FC = 39.5 Measured using the FAS-DPD Taylor test kit. 10ML from pool 2 dippers of R-0870, 79 drops of R-0871 reagent.
PH = 7.6
CYA = Could be as high as 200, hard to measure past the 100 level.
CC = 1
TA = 170

I would rather not drain 2/3 of the pool due to the high cost of water in my area. I purchased 8 gallons of bleach but am holding off until I have a better strategy from a "pro" here. I also purchased "yellow out" but have not used it yet. I have two boxes of 76oz Mule team borax on hand also.

I have an 18,000 gunite in ground pool. Hayward C3000 cartridge filter.

What are my options and detailed steps to get the pool back from the algae and CYA monster.

Thank you in advance
Bob

P.S. If it makes any difference, my neighbor's pool is worst than mine with algae. Would that effect my pool?

 

[heythatguy]

If you want to get a more accurate test result on the CYA, mix equal parts pool water and tap water, then perform your test and multiply that number by two. With CYA levels that high it will be a hard battle to rid your pool of that algae.

 

[chem geek]

Welcome to TFP!

You are clearly going to need to do a significant drain/refill if your CYA is truly that high. It would take extraordinary amounts of chlorine to kill off the algae and clear the pool with a very high CYA level and it will take very high Free Chlorine (FC) levels to maintain the pool after that.

If the "yellow out" product is sodium bromide, then using that will turn your pool into a bromine pool and the bromine will likely kill the algae as bromine does not get moderated in its strength with CYA, but you'll have a bromine pool with its higher cost of maintenance.

 

[vans4]

Thank you for the quick replies. I added equal parts pool and tap and my CYA is still hard to read as it is well over 100.

It looks like I will have to drain and refill. Since it is the end of the season, what about trying to fill it with rain water during the fall winter spring months?

The local pool company says it has been the worst year for algae and high CYA pools that they can remember. It sure is for me. I used to be able to float 3" chlorine pucks and be fine.

 

[heythatguy]

In my area it has been an above normal year for algae, a lot of late algae as we are still in the 90's ans 100's. Fill it as soon as you have it drained. You do not want to risk plaster popping or cracking. Make sure to test your tap water for the ph, and do not forget to set your cya at the proper levels 30-40ppm.

 

[chem geek]

From the reports of forum users who are properly following the Chlorine / CYA Chart, this is not an unusual year for algae (i.e. there aren't reports) since proper chlorine levels prevent algae growth regardless of algae nutrient level or how much algae is blown in from the air. There are many new users coming to the forum with algae, but it's hard to know if the number is substantially higher proportionally since overall forum traffic is up.

As for diluting the water, you can use winter rains for that if you want to wait this out. You'll still have algae of course, but at least you can get your CYA level lowered which you need to do regardless. Once the CYA is lower, you'll have an easier time getting rid of the algae. In the meantime, it's hard to say what to do. Keeping very high FC levels will somewhat keep the algae from growing as fast, but it may take a lot of chlorine unless you get ahead of that algae growth. If you do, then you can just ride it out until winter rain dilution.