Copper algaecide recommendations?

[cflannagan]

Never used those before, looking to do 0.5 ppm for our 18k gallon pool (see signature), NO MORE than that. Do those come in different forms (solid, liquid), or is it relatively straightforward? Any brands to avoid, any brands you would recommend?

 

[ajw22]

NONE!

0.5 ppm of copper in the water can cause copper staining.

Why do you want to add copper?

Copper in Pool Water - Further Reading

www.troublefreepool.com

 

[JamesW]

You have been here 14 years and you do not know that we tell people to never use copper?

Seems odd.

 

[cflannagan]

The days are getting warmer here, and the the black algae spots are returning again for like 5th or 6th straight time and will menace us thru the entire swimming season. If you look through our post history, we have had a history of this issue.

Yes, we shock our pool and maintain the proper shock level for recommended period of time (using the SLAM method explained elsewhere)

We are at our wit's end, truly. We have tried all suggestions here including elbow grease (shocking the pool, scrubbing the spots, and so on). Nothing has kept them away.

Part of the problem I think is we have a peebletec finish, so the black algae spots "blends" in some with our peebletec finish, so if we think we scrubbed all away, those spots return eventually, so we think we probably missed spots that were obsfucated by our peebletec finish.

I've read that copper algaecide is the most effective against black algae.

I am not surprised the advice is to stay away from the copper algaecide, completely understandable. But I need something other than "yeah, it just takes some elbow grease, keep scrubbing as they show up", that simply doesn't work. Is there something else we can try other than what was mentioned?

We are seriously thinking of doing a new finish on our pool that's NOT a peebletec finish, just so we can see the black algae spots better and scrub them away 100%. We have never had this type of issue until we went with a Peebletec finish; before that it was just plain plaster finish. At times I feel like the family has lost a lot of interest in swimming because of those unsightly black algae spots.

 

[ajw22]

At times I feel like the family has lost a lot of interest in swimming because of those unsightly black algae spots.

Do you think your family will find more interest in swimming with copper stains in your pool?

 

[cflannagan]

Do you think your family will find more interest in swimming with copper stains in your pool?

That's why I mentioned staying under 0.5 ppm. Unless that doesn't matter either, I guess

Is there anything else we can do here besides the usual "SLAM and elbow grease" which hasn't worked based on past 4-5 years worth of experience? Short of going with a new finish just so we can see the spots better

 

[PoolStored]

But I need something other than "yeah, it just takes some elbow grease, keep scrubbing as they show up", that simply doesn't work. Is there something else we can try other than what was mentioned?

Pick at the black algae spots with some sort of physical method: wooden stick, wire brush, or, my personal favorite, weak pressure washer. Then, apply the strongest LC to those spots: pump sprayer, dump jug over the spot—more than once is better. Then run FC hot.

You have to disrupt the black algae. If you have less than ten spots, use a bamboo BBQ skewer. If you have more, a weak pressure wash will make quick work of it. Get in the pool with a mask and snorkel and have at it. Some do not like the wire brush method and think it is too aggressive.

For the pressure wash, something like a 2500 psi with a 15 degree nozzle. Or 3000 PSI with a 25 degree nozzle. Also distance from the plaster matters a lot. Get close enough to pop off the algae but not close enough to damage the plaster.

Also will depend on the age and condition of your plaster. In any case this method seems to be less aggressive than a wire brush.

Use common sense and be careful.

Then, apply the strongest liquid chlorine to those spots. Either dump it and let it flow over, or get a pump sprayer. Some have gotten lazier over the years and just dump. It uses more chlorine, but you probably need to raise your level anyway.

Run your FC at 20% of CYA for at least several weeks.

This is the part that sucks; run your FC on the high side in the future at a minimum of 12% of CYA; 15% is better to try and keep the black algae at bay.

 

[ajw22]

That's why I mentioned staying under 0.5 ppm. Unless that doesn't matter either, I guess

That is no guarantee you will not get copper staining.

 

[cflannagan]

Pick at the black algae spots with some sort of physical method: wooden stick, wire brush, or, my personal favorite, weak pressure washer. Then, apply the strongest LC to those spots: pump sprayer, dump jug over the spot—more than once is better. Then run FC hot.

You have to disrupt the black algae. If you have less than ten spots, use a bamboo BBQ skewer. If you have more, a weak pressure wash will make quick work of it. Get in the pool with a mask and snorkel and have at it. Some do not like the wire brush method and think it is too aggressive.

For the pressure wash, something like a 2500 psi with a 15 degree nozzle. Or 3000 PSI with a 25 degree nozzle. Also distance from the plaster matters a lot. Get close enough to pop off the algae but not close enough to damage the plaster.

Also will depend on the age and condition of your plaster. In any case this method seems to be less aggressive than a wire brush.

Use common sense and be careful.

Then, apply the strongest liquid chlorine to those spots. Either dump it and let it flow over, or get a pump sprayer. Some have gotten lazier over the years and just dump. It uses more chlorine, but you probably need to raise your level anyway.

Run your FC at 20% of CYA for at least several weeks.

This is the part that sucks; run your FC on the high side in the future at a minimum of 12% of CYA; 15% is better to try and keep the black algae at bay.

Appreciate it - this is something new for us to try!

When you say pressure wash, is that as in pressure washing underwater? (I didn't know that was possible). The spots often form in the area nearby where spa waterfalls into our main pool, about 3-4 feet deep. Pressure washing underwater would probably require special equipment? We have a pressure washer, but I'm not sure it's a type we can use underwater. will look into this

What's LC and FC? I assume LC is liquid chlorine, what is FC? (My brain is saying "free chlorine", but thats not right for this context is it, does FC mean something else?)

(I might have a couple more questions about what you just posted, again I appreciate new suggestions, we are willing to try anything)

 

[PoolStored]

You only take the wand into the pool. Do not put the actual pressure washing unit into the pool.

LC= Liquid Chlorine
FC = Free Chlorine, what you measure with your FAS-DPD chlorine test.

Start further away and slowly get closer. You just want to blow the algae away, not damage plaster. Start with a wider tip, like 45 degrees. Then work your distance and the head angle degree until you get the right balance.

Red not in pool, green in pool.

 

[ajw22]

@Katodude in Florida developed that method of attacking black algae.

 

[cflannagan]

You only take the wand into the pool. Do not put the actual pressure washing unit into the pool.

LC= Liquid Chlorine
FC = Free Chlorine, what you measure with your FAS-DPD chlorine test.

Yeah, upon re-reading some materials, I realized I had a brain fart, was thinking free chlorine was the one that includes the organic contaminants (the "free" part keep throwing me off), but is in fact CC (combined chlorine). I got my brain re-calibrated here.

Start further away and slowly get closer. You just want to blow the algae away, not damage plaster. Start with a wider tip, like 45 degrees. Then work your distance and the head angle degree until you get the right balance.

Red not in pool, green in pool.

View attachment 637753

Yup, wasn't gonna take the red into pool but good callout, just in case haha. Think I might need to get a long wand, if I don't have one already, to better assist with this task.

We tend to keep CYA at around 60 (making it easier for our SWG to maintain "shock" or "near-shock" levels). 12% to 15% would be 7.2 to 9 ppm FC. Noted in my head now.

We'll start off with 20% (at least 12 ppm FC) for several weeks. It might already be there because we just turned SWG knob up high when we started seeing black spots. Will test pool numbers tomorrow to see where we stand at, FC-wise.

@Katodude in Florida developed that method of attacking black algae.

Which method? Oh, the one PoolStored just went over? That's a good sign if it worked for him too here in Florida

 

[proavia]

What test kit are you using?
Add it to your signature - https://www.troublefreepool.com/account/signature

Are you using PoolMath ?
You can link PoolMath to your forum account so we can see your test results when hovering over your username/icon in the left column and clicking PoolMath Logs.

Post a full set of current test results

FC
CC
pH
TA
CH
CYA
Salt
Water temperature

 

[cflannagan]

What test kit are you using?
Add it to your signature - https://www.troublefreepool.com/account/signature

Are you using PoolMath ?
You can link PoolMath to your forum account so we can see your test results when hovering over your username/icon in the left column and clicking PoolMath Logs.

Post a full set of current test results

FC
CC
pH
TA
CH
CYA
Salt
Water temperature

I have the TF-100 test kit, same one generally recommended around here.

Using PoolMath: yes. I have the Pool Calculator bookmarked. Setting: 18k gallon, plaster finish, SWG, using Trouble Free recommended levels.

I plan to test pool water tomorrow and share the results, but in general, on average, I can expect to see those levels:
~8 or so ppm FC
pH tends to be around 7.2 to 7.5. I put some acid in on a weekly basis or every 2 weeks (depending on how fast pH is changing)
TA I try to maintain at around 80 (and is probably around that at the moment)
CYA I try to maintain at 60 (as opposed to 70 or 80), to make it easier to shock our water which we seem to have to do often whenever we see black spots
Salt is ~3300 or ~3400 last time I checked.
Water temperature was around 80 when black spots formed. As of now, water temperature is probably a bit lower due to cooler Florida weather

I will share the actual numbers tomorrow. Just know that even when I maintain proper levels (and starting with usual SLAM method at start of swim season), the black algae spots will return stubbornishly as they have been. I have pretty well-documented history of asking for help on black algae in the past in this forum.

 

[Katodude]

The method described by @PoolStored is the one I recommend. You dont need a special wand or anything. But you will need a mask and snorkel. Get in your pool and blast those spots away. It’s oddly satisfying.

Then you need to attack the freshly blasted spots with high dose LC. Either use a pump sprayer or dump the LC and watch it wash over the area. This is what I do now since I am a little lazier. Go to Leslies and buy their 2.5 gallon refillable jugs for LC. It’s the strongest and cheapest stuff around. It’s also yellow so you can see it wash over the areas you had blasted. You will waste a bunch of LC doing it that way but who cares it’s going in the pool anyway which you will need. You will want to keep your FC at 20% of your CYA for several weeks.

Now welcome to the Black Algae club. The moment your FC dips you will get it again. Just plan on having your FC at least 15% of your CYA for the rest of the life of your pool.

At this point I consider 10 my minimum for FC.

 

[PoolStored]

Now welcome to the Black Algae club. The moment your FC dips you will get it again. Just plan on having your FC at least 15% of your CYA for the rest of the life of your pool.

At this point I consider 10 my minimum for FC.

I think this is really important. If you use 15%, or 9FC for CYA of 60...you should be fine.
Remember, it is safe to swim with FC up to SLAM level. The recommendation would be to keep your FC higher, so that you never go below the 9. Requires different thinking...

 

[JoyfulNoise]

When you are ready to resurface your pool, I would suggest you use a mechanically polished plaster with no aggregate. Hydrazzo plaster is very well regarded for that type of finish but it is expensive and it does require the applicator to be trained and know what they are doing. The polishing process creates a very smooth and dense surface that will be more resistant to the black algae you experience and it will be much easier to spot if it ever comes back.

There’s really not much you can do about your current finish - the black algae has set roots (hyphae is the technical term) into the plaster surface and there just no way to kill them. Copper algaecides will kill the budding algae but probably not any of the hyphae. So even that is not a foolproof method. It will cause ugly staining of the plaster which will be a nuisance to fix as it requires draining the pool. The above chlorine wash method works but it too has its limitations.

Sorry that you have to deal with black algae, it’s a royal PITA when it shows up.

 

[Katodude]

Hmmm. The Hydrazzo seems intriguing. Going to have to put that in the memory bank for when I need to replaster my pool in 10-15 years.

Requires different thinking...

This is important, and becomes difficult to fathom as you raise your CYA. Once you are free and clear of all algae I recommend that you up the CYA level to 70 or even 80 as that will be easier for your SWG during our Florida summers. Since you have a pool cage you might get away with the lower level.

But people tend to freak out when their FC is 15. For me 13-15 is ideal. It gives me a buffer if we have a crazy rain, and I travel frequently so I like that buffer as well.

However, my pool is the cleanest in the whole neighborhood.

 

[ajw22]

Hmmm. The Hydrazzo seems intriguing. Going to have to put that in the memory bank for when I need to replaster my pool in 10-15 years.

I have had Hydrazoo finish for 25 years in my pool and it wears very well. It is a premium product at a premium price.

 

[Newdude]

However, my pool is the cleanest in the whole neighborhood.

+1 @cflannagan. Welcome to #teamrunhot.

Many of us are members without any black algae concerns. The water is stoopid clear and there's a 2 day reserve of FC for anything the universe might throw our way from a big storm hitting unexpectedly or a particularly high UV day.