Algae on Stairs - Driving Me Crazy

[Csmokem]

This is my first post, but I have been lurking here for years. I want to say thank you in advance for the help this forum has provided over the years as I am sure it has saved me hundreds in pool chemicals! I will try to keep my post brief and upload pictures later this week if needed.

Problem - Algae on stairs - Black in cracks and pits on the (fiberglass?) stair case?. This stuff will not die (if this is the problem) and if I let my chlorine drop below 10ppm I start seeing a brownish/redish slime on the stairs.

Treatment - when I first opened the pool this year, I swore I would beat down the stair monster and I nuked the pool for 3 days at 50+ ppm.

Current Pool Status - Blue sparkling water - just totally annoyed with the stair monster

PH- 7.6
CYA - 80-90
Alk - 90
Salt - 2700 ppm
Calcium - 400 ppm
Borates - 50ish ppm
FC - 23 ppm
CC - 0

Vinyl Liner
Sand Filter with DE alternative added for better filtration
Chlorine Method - Liquid 10.5% Bleach only unless away for extended period then I add Trichlor pucks, I don't have a chlorinator
Polaris and 1.5 hp pump
25000~ gallons

Any advice you can give will be greatly appreciated!

 

[Texas Splash]

Just to be safe ... can you confirm what test kit was used to get these readings please?

 

[Csmokem]

TF-100 with Speed Stir - only way to go!

 

[Texas Splash]

Amen to that. Well, anytime you see algae, that's an indication you need to SLAM, and that your FC is either too low or getting used-up too quickly. Your CYA is getting high (70-80 for SWG, 30-50 for Non-SWG), so that may be interfering with the chlorine's effectiveness as well. Curious to see what other TFP'ers have to say as well.

 

[Patrick_B]

Welcome to the forum!

Nuking for 3 days at 50 won't do the job, and it could be really bad for your pool. I agree with the conclusion from above. You need to perform a full and complete SLAM process on your pool. Review the process, follow it to the letter, and post back here for help. We will be glad to pitch in and help you along. You need to reduce the Cya, as it is too high. 30-40 at most would be ideal. Being over stabilized is a part of your problem now.

 

[Csmokem]

My apologies, I obviously did not give enough information.

The nuking of the pool at 50+ ppm Chlorine was the SLAM that I performed about 1 month ago. It took 3 days at that level with my CYA at 80ish to pass the overnight test. The poolcalc showed a mustard algae shock level of 44~. This was about 5 weeks ago. Over the holiday weekend with the amount of rain we had, it my free chlorine level was down to 4 and and low and behold- the stair monster was back. I have used the SLAM method every year since 2009 to open my pool. I just really thought my algae problem on the stairs would be gone this year as I was methodical in testing every night and every morning during the SLAM That is why I am posting now for any insights. I will be home this weekend and have the time and patience to SLAM again if that is what is needed... but I am fearful that the chlorine is just not getting into the cracks/spots on the stairs to clear it out completely.

 

[TomBorg]

Yeah, my thought is that there is poor circulation around the stairs, and the chlorine is used up faster than it is replenished by water flowing in.

Can you adjust one of your return jets (eyeballs) to point towards the stairs? Or adjust all of your returns to get a nice circular movement of water throughout the pool?

 

[Patrick_B]

Ok, more complete info helps us give you a much better answer. You may have poor circulation there, but maybe you didn't kill everything in there. When you do, and you have a reasonable amount of activity in the pool, maybe a daily brushing in the area in between to keep freshly chlorinated water there, your problems should be minimal to Zero.