Mustard/Yellow Algae Help PLEASE!

Hello,

AG pool, vinyl lined with deep end, 13,500 gallons, sand filter. I use strictly BBB, and I use the PS233 test kit.

pH 7.2
TC 7.5
CC 0
FC 7.5
TA (80-90)
CYA 38

Last week and this week, we have been having 90's during the day, and for a few days last week, I did not remove the solar cover from the pool. I opened one day to a tiny bit of cloudiness, which surprised me as my numbers were perfect. It had rained a lot over 3 days time, so I thought it had something to do with that. The next day I opened to a messy, yellow pool with stringy things on the bottom. I'm assuming mustard algae. I was told that I should not have left the solar cover on over the hot weather, even though it was cooler at night and I only did it for 3 days. My fault...live and learn I guess.

So....going by some posts I read here, I raised to shock level for 2 days straight, left the solar cover off, and the filter (sand) running 24/7. After 2 days, all the yellow is gone, but it is still just slightly cloudy. How long will I need to keep it at shock level (15, correct?) before I can expect the cloudiness to go away and I can resume normal maintenance? Or could the cloudiness be due to low TA? I was told this TA was okay a couple weeks ago.

Another couple questions: When testing for TA, do you want the green test water to turn bright pink, or do you measure when it turns from green to a slightly light pink color? The reason I put 80-90 for the TA reading is because at 80, it is only slightly pink, but at 90 it is really bright pink.


Also, is it safe to swim in a pool that is at shock level? We don't, but I am just wondering.

Thanks for any and all help.

Sandy

You can leave your alkalinity where it is - I would say it is 90, and that is fine. You will have to keep your chlorine at 15 until the water clears completley, and the chlorine holds overnight. You will also have to keep your FC at a minimum of 6 when finished dealing with mustard algae, as it comes back really quickly. You may also want to add some polyquat 60 algaecide. It won't kill the algae, but it can help prevent it coming back when it is gone.

It is ok to swim with chlorine levels of 15. I have gone swimming in my pool with chlorine up to 25. The only thing you may want to do is to wear an old bathing suit. Mine did not fade even at levels of 25:), but I like to warn just in case.

Most important- you should try to keep the chlorine at shock levels, testing as often as you can and bringing it back to 15, 3x a day if you can - being consistant will kill the algae faster, and clear the water. Make sure you brush and backwash often too. Keep it at 15 until the water clears, and the chlorine holds overnight.

Quote:

---

Originally Posted by SandyDittmer

The next day I opened to a messy, yellow pool with stringy things on the bottom. I'm assuming mustard algae.

Sandy

---

Hi Sandy,

Could you describe a little more about the algae? You mentioned stringy things on the bottom. Was the pool water yellow with stringy things? or the stringy things on the bottom yellow?

Do you have any pictures from above the water? or close-up?

did you vacuum with a skimmer sock? do you still have that to show what the substance looks like?

What type of filter do you have? if it's a cartridge filter could you snap a few pictures before you clean it?

Thanks so much!
dan

Hi Dan,

The water was very murky, milky, cloudy, unclear, with a slight yellow hue to it. The stringy things were about an inch long or so on the pool floor, and they were a yellowish green color. I wish I had taken pictures of it, but unfortunately I did not.

I have been battling for a week now with tons of bleach. The water looks about 90 percent better. It still is not sparkling clear like I normally have it though. It is slightly cloudy, but just barely. We have a sand filter. Strangely enough, the pressure is not going up much on the filter. I have backwashed once, but it does not seem to be going up at all. This may be due to the fact that I am not manually vacuming the pool but using a robotic cleaner (Dolphin Diagnostic).

The pool cleaner also climbs the walls. The filter bag filters down to very fine dust and algae according to the manufacturer. I did manually brush the pool once to get up anything I saw that the cleaner may have missed. The sides and bottom look clear of any algae.

I don't know how to get back the crystal clearness. It is getting frustrating. I honestly don't know if it was mustard algae or just the regular green stuff. Now the weather is cooling and we will most likely close within a few weeks.

Today I did add about 12 oz. of Polyquat algaecide. I know it doesn't kill, but will hopefully prevent more from coming back.

If you have any suggestions, by all means feel free to let me know. It has been very discouraging to lose a whole week of swimming time to this battle. Our kids have still gone in even in high chlorine levels and when it was icky looking, but with the solar cover off, the water is really getting chilly. We are whimpy when it comes to cold water.

Thanks for your help,

Sandy Dittmer

It sounds like your on the right course...continue to KEEP levels up at a high level shock (in case it is mustard algae) until the water looks good and you have no chlorine loss overnight. It sounds like you may be close...so keep it up.

dan

Greetings--

We've had a rough season this year with mustard alge. The pool store and several of the service guys I see around have all said that this has been a rough year here (Texas).

We run our filter 24x7 now. A careful watch on the CL levels and pH has helped. After the first serious outbreak -- we got that one cleared up with two good doses of Eliminator (Sodium Bromide I think)and serious shocking over a two week period.

Its much better, but I do see it start to come back if the CL levels drop. We've been trying to keep them above 4, and if we're going out of town, raise them up to 6-8 or so.

Quote:

---

Originally Posted by Piney

Greetings--

Its much better, but I do see it start to come back if the CL levels drop. We've been trying to keep them above 4, and if we're going out of town, raise them up to 6-8 or so.

---

Hi Piney :)

If you get ANY deposits could you send me a sample, please?

Also...if you could take a picture from above the water would be helpful as well. Does it "stick" to the bottom or sides? or does it easily get stirred up?

But I would also like to see you "suck" up a sample of this algae from the bottom of the pool.

To collect it...Take your pool water sample bottle or some type of squeeze bottle (with the dropper tip) and squeeze out all the air above water. Then exhale and SLOWLY swim to the bottom of the pool where some of the mustard algae is. Once you gently approach the algae with the dropper tip start to release the pressure on the bottle to draw the algae into the bottle. Do this in a couple of different spots until the bottle is full of algae and water. Next...slowly pour the water over an old pair of nylons to filter out the algae letting the water flow thru. Then you could put the remaining algae in a ziplock bag and send it to me for some closer examination under the microscope.

If you would be able to help out send me a private message and I'll get you my e-mail.

thanks!
dan

Quote:

---

Originally Posted by Piney

Its much better, but I do see it start to come back if the CL levels drop. We've been trying to keep them above 4, and if we're going out of town, raise them up to 6-8 or so.

---

Piney,

What's your CYA level? I just want to see if the rule of needing an FC of 15% of the CYA level for preventing yellow/mustard algae applies to your pool (the rule for green algae is a minimum FC of around 7.5% of the CYA level). That would imply a CYA level of about 25-30 ppm for your pool. If you have a higher CYA, then your yellow/mustard algae isn't as aggressive as in some other pools, possibly due to limited nutrients or environmental conditions.

Richard

Quote:

---

Originally Posted by Piney

Greetings--

We've had a rough season this year with mustard alge. The pool store and several of the service guys I see around have all said that this has been a rough year here (Texas).

We run our filter 24x7 now. A careful watch on the CL levels and pH has helped. After the first serious outbreak -- we got that one cleared up with two good doses of Eliminator (Sodium Bromide I think)and serious shocking over a two week period.

Its much better, but I do see it start to come back if the CL levels drop. We've been trying to keep them above 4, and if we're going out of town, raise them up to 6-8 or so.

---

I can't keep my chlorine levels up, can I use chlorine bleach to get the level of chlorine up, even if I have been using chlorine shock? What else can I do? I want to close the pool, but I know I have to get rid of the algae first.

Quote:

---

Originally Posted by skystone

I can't keep my chlorine levels up, can I use chlorine bleach to get the level of chlorine up, even if I have been using chlorine shock? What else can I do? I want to close the pool, but I know I have to get rid of the algae first.

---

Yes, you can use bleach...it's all chlorine once it gets into the water....

Janet