Mustard algae?

[dariushd]

Non-salt-water: I think I have the yellow mustard that grows on my walls, almost entirely in the shade, even 2-3 days after brushing. I am fighting a CYA level of 200+ and am planning most likely an 80% draining (my CH level is 400 too) or an RO treatment if my house water tests hard, too. Here's a photo from underwater that shows the bit of yellow algae (less than a week after brushing). Another forum member told me the discoloration on the walls is likely due to calcium scale, so it really looks like a drain is in order when my chlorine drops to 0. Can I use a de-chlorination chemical to speed this up, or just wait it out?
The guy at Leslie's actually told me NOT to but the chemical and let the sun do it to be safe.



Once my chemistry is normal after a refill or RO treatment, should I expect not to see that algae again, or do I still need to brush the pool weekly or more?

 

[kcindc]

I've asked the mods to move your post to its own thread so you can get specific info relating to your specific issues.

With a very high CYA, you are unable to adequately have enough chlorine to keep regular green algae at bay. As such, I strongly feel like you have a regular algae issue. Until you have reduced you CYA levels, it will be impossible to address. Either a drain or RO needs to be completed first.

What test kit do you have? What kit gave you the high CYA result?

Recommended kits (TF-100 XL is the most economical when defeating algae):
Pool School - Test Kits Compared

Once you get your CYA in order, you will need to complete a SLAM to get rid of the remaining algae. I suggest reading up on pool school articles on SLAMing:

Pool School - ABCs of Pool Water Chemistry
Pool School - SLAM - Shock Level And Maintain
Pool School - Chlorine / CYA Chart
Pool School - Recommended Levels
Here is one on calcium scale:
Pool School - Calcium Scaling

 

[dariushd]

Thank you for moving the post, much obliged.
I am about to schedule an RO treatment, and though it's a couple hundred bucks more expensive than just a refill, I think it may be worthwhile. Anyway, I assume I should SLAM the pool after the RO treatment to kill off the algae, and not use any algaecide?
I'll have the K2006 in a day or two.
I'd also like to remove the discoloration ont he walls and floor you can clearly see in there. Another forum member mentioned it could be calcium and to reduce pH for a while. Any thing else I can do to better identify the discoloration like pour some acid on it and see if it disperses (which means it's calcium, right?).

 

[kcindc]

Hi Dairush,

Algaecide doesn't kill algae and will only prevent algae. Algeacide is best used as insurance when you go on vacation, when you need to do metal treatments and when closing a pool for the winter (for those of us who live in colder climates). The most effective and the cheapest way to kill algae is with regular bleach found at Wal-Mart or your grocery store which is usually the 8.25% stuff. Some folks pick up 10% chlorine from pool stores or hardward centers, but make sure to check the date as the stronger stuff looses strength faster and some places let this stuff sit for months.

Happy that you have ordered up one of the recommended kits. The K-2006 is a good kit, but you might find that you don't have enough reagents to get through a SLAM. It only has enough for about 25 tests. Keep an eye on your reagents, but you should consider ordering more FC testing reagents. Most local pool stores do not carry FAS-DPD testing supplies. TF Test kits is a great place to get more.

In the mean time, you can add a gallon of 8.25% bleach a day to keep things from getting worse.

Post up a full set of results when you get your kit. More than likely it is calcium, but some good pics of the trouble spots should help us identify it. Generally, calcium scale is removed by having slightly negative CSI and scrubbing with a pumice stone. It is best to address the scale after the RO and after you have SLAMed your pool to get rid of the algae.

You've come the right place and we will help you get your pool sparkly again