Dealing with dead algae dust

[Krulligo]

This is my first time dealing with algae since I switched to TFP method back in the spring of last year.

Short story of what happened is that I didn't add enough chlorine before a really big storm at night, with lots of wind and water accumulation. Unfortunately the morning after the storm, with dealing with a toddle and a baby, I didn't have time before going to work to deal with the pool and it passed my mind to up the chlorine level. After coming home I checked the pool and it went slightly cloudy with a slight hint of murky green. Some green-brown dust at the bottom in certain areas that can be brushed off. However can easily see the bottom (4f deep round pool). I measured the chlorine level and it was at the lower end of the range for my CYA. I quickly added enough chlorine to up to SLAM level (30 CYA - added up to 12ppm chlorine). A few hours later I remeasured and added a small amount to get it back to 12ppm.

Before going to sleep at around 11pm, I measured chlorine to do an OCLT and it measured 12ppm. This morning I got up before the sun to measure again and chorine was at 11.5ppm with no CC detected. So I think I have killed off the living algae already (since I probably caught the bloom very early).

Just wondering what my next steps should be since the pool is still cloudy. It has been filtering through a sand filter for about 15hours and the pressure in the filter is very slowly rising. Will the sand filter be able to capture what I suspect is dead algae dust with running it 24/7? How long could it typically take to clear? Is there anything else I should do?

All other tests were not out of the norm - TA=80ppm, pH=7.8 (this measurement was done at SLAM level so probably inaccurate, a few days ago I measured it at 7.3-7.4 but might have gone up due to the rain).

 

[wireform]

Keep the slam going as you haven't achieved the 3 criteria and cloudy surely isn't a finishedslam. After crystal clear keep it one more day for extra insurance. PH isn't accurate with FC above 10 so leave it alone till the slam is over with a full test showing all the levels.

 

[Krulligo]

Keep the slam going as you haven't achieved the 3 criteria and cloudy surely isn't a finishedslam. After crystal clear keep it one more day for extra insurance. PH isn't accurate with FC above 10 so leave it alone till the slam is over with a full test showing all the levels.

Thanks. Will the sand filter out the dead algae? Or should I turn pump off, let it settle to bottom and then vacuum to waste?

 

[Krulligo]

So pump/sand filter have been running for 24 hours now. Pool clarity doesn't appear to be any worse or any better. The pressure on the filter gauge initially rose very slightly, but has stayed steady for 20 hours now. Last nights OCLT was a pass, and there was what I would call a normal amount of chlorine loss throughout todays sunny day and never measured any hint of CC. My guess is that all algae is dead but the dead algae dust is just passing through my sand filter and back into the pool? The sand in the filter is probably quite old (we moved into the house 3.5 years ago and I have never put in fresh sand). The pool is currently in slam levels, and is still cloudy but bottom of the pool is clearly visible.

Is this something that I can and should do while my pool is in this state in mid summer?

What about using a product such as a clarifier? Would that help? Any suggestions would be helpful.

 

[VinnyinNJ]

Don't use anything in the pool water! Anything other than recommended chemicals will make matters worse. Sand filters take a while to clear up a pool, something you can try is to get some filter diatomaceous earth (DE) and put a little bit into the sand filter and watch for a 1 PSI rise. There's info on this site about it, basically you take a little (1/8 to 1/2 cup depending on size of filter - always start low), mix it in a bucket with water and pour it into the skimmer, watch for a pressure rise of 1 PSI and let the DE help the sand. With DE in the filter you will have to watch it as the pressure may rise quickly as the DE filters out the debris. Once the pressure gets to 25% more of starting pressure, backwash and start again. As for anything that has settled on the floor - vacuum to waste may be a great idea assuming you're OK with being able to replace the water being "wasted".

If you ever added anything (flock or clarifier) to your pool water in the past it is possible that the sand is gummed up and should be replaced - there is a procedure on deep cleaning a sand filter that should be done at the beginning of each season.

 

[duraleigh]

Stay the course. You are doing all the right things and your pool will clear......just not as fast as you would like.

As said above, please don't add anything else to your pool. Following the SLAM article precisely will result in a crystal clear pool.

I am not a big fan of vacuum to waste in almost every case, including yours........I think it discards wa-a-a-ay too much water

The SLAM value chlorine will oxidize the algae "carcasses" if you will brush them daily up into the chlorinated water. It may cloud your pool again but it is temporary. Don't worry about algae getting through your filter.

I do think you should set aside some time to open the filter and deep clean your sand. About every 2-3 years seems right and it sounds like you are due.

 

[Krulligo]

Stay the course. You are doing all the right things and your pool will clear......just not as fast as you would like.

As said above, please don't add anything else to your pool. Following the SLAM article precisely will result in a crystal clear pool.

I am not a big fan of vacuum to waste in almost every case, including yours........I think it discards wa-a-a-ay too much water

The SLAM value chlorine will oxidize the algae "carcasses" if you will brush them daily up into the chlorinated water. It may cloud your pool again but it is temporary. Don't worry about algae getting through your filter.

I do think you should set aside some time to open the filter and deep clean your sand. About every 2-3 years seems right and it sounds like you are due.

Thanks makes me feel much better.

Just a few updates. I completed a second OCLT this morning and once again only lost 0.5ppm or less with no CC so feel confident that algae is all dead.

I decided to leave the pump off overnight and try to let things settle to the bottom to see if it's worth vacuuming. Luckily when I went out this morning to take a look, the pool water did look quite a bit clearer. I didn't immediately see much at the bottom so I took the brush and agitated a small area of the floor and a greenish-brown dust cloud did appear. So I did decide to vacuum the bottom the waste since my pool is small. I did see a noticable different on the spots I was vacuuming - quite a bit more blue compared to a greenish tint at spots where I did not vacuum.

After vacuuming the floor to waste. I filled the water back up and it looks considerably better but still a hint of cloudiness. I am now hoping the sand filter and slam levels of chlorine will do the rest.

I am also going to buy a bag of DE as I always wanted to try charging my sand filter with it and I think now is the time to do it.

I am sure the previous owners did use clarifier as they had this in the chemicals they left for me. And as I said, I do not know how old the sand is as it predates to me moving into the house. I am now planning to run with the current sand for the rest of the year as it has been ok so far, be more diligent in keeping chlorine up especially when alot of rain is expected, and open up the sand filter to take a look and possibly deep clean or change it up early next spring.

 

[Rancho Cost-a-Lotta]

I am also going to buy a bag of DE as I always wanted to try charging my sand filter with it and I think now is the time to do it.

Add DE to a Sand Filter

A clean pool filter will increase the efficiency of your pool! ... your filter are to backwash it, clean the manifolds and grids, and add new DE.

www.troublefreepool.com

 

[Krulligo]

So I am on my third day or slam now. Once again passed ONCT. Water is clear but I would say it's dull/slightly cloudy. Definitely not as sparkling as it should be.

I thought about DE and am a bit reluctant to add it as I don't know the state of the sand inside the filter and whether there is channeling etc. I just don't want the DE to be blown back into the pool and create a new mess to deal with? Is this a possibility of happening or should the sand capture the DE?

Any other tips from cleaning our the final fine particles to get clear water from looking dull to sparkling clean without the use of products like clarifier/condition. It feels like the sand filter alone isn't doing much anymore to get it clearer, or should it clear up over the next few days?

 

[Bperry]

So I am on my third day or slam now. Once again passed ONCT. Water is clear but I would say it's dull/slightly cloudy. Definitely not as sparkling as it should be.

I thought about DE and am a bit reluctant to add it as I don't know the state of the sand inside the filter and whether there is channeling etc. I just don't want the DE to be blown back into the pool and create a new mess to deal with? Is this a possibility of happening or should the sand capture the DE?

Any other tips from cleaning our the final fine particles to get clear water from looking dull to sparkling clean without the use of products like clarifier/condition. It feels like the sand filter alone isn't doing much anymore to get it clearer, or should it clear up over the next few days?

Just keep brushing up clouds so the filter can catch it. I’m also not a fan of the DE in the filter because of the potential to get back into the pool.

 

[duraleigh]

I agree with bPerry. Brush the cloud up into the water. It is really helpful.

It seems you have passed SLAM except for perfectly clear water. I would lert the FC drift down to about twice your normal FC and hold it at that elevated level for a couple more days. You are very close......please no pool store magic potions!

I would get the pool clear first and then pop the lid on that filter and see what you have there is an article in this forum about deep cleaning a sand filter and it is EXCELLENT, Common sense will guide you but the article is a great reference.

 

[Krulligo]

I agree with bPerry. Brush the cloud up into the water. It is really helpful.

It seems you have passed SLAM except for perfectly clear water. I would lert the FC drift down to about twice your normal FC and hold it at that elevated level for a couple more days. You are very close......please no pool store magic potions!

I would get the pool clear first and then pop the lid on that filter and see what you have there is an article in this forum about deep cleaning a sand filter and it is EXCELLENT, Common sense will guide you but the article is a great reference.

Thanks. Yea I have been constantly brushing whenever I can however doesn't seem like its getting any better now but might just need some more time. My pressure on my sand filter gauged has stopped going up. Normally is at 12PSI when backwashed, and now is closer to 13, but hasn't really moved in the past 24 hours which is why I am skeptical that it is catching the finer dust. Will the chlorine eventually degrade this dust up or is the key to capture it by the filter?

 

[Bperry]

Thanks. Yea I have been constantly brushing whenever I can however doesn't seem like its getting any better now but might just need some more time. My pressure on my sand filter gauged has stopped going up. Normally is at 12PSI when backwashed, and now is closer to 13, but hasn't really moved in the past 24 hours which is why I am skeptical that it is catching the finer dust. Will the chlorine eventually degrade this dust up or is the key to capture it by the filter?

The sand filter can catch very fine particles, it’ll be fine it just takes time.

 

[wireform]

I find that eventhough it's recommended to backwash when the psi hits 25% higher of clean filter pressure, I still let it go more for end of slam as the dirt in the sand actually help trap more dirt where as the fine stuff doesn't get caught as well with a cleanly backwashed sand filter.

 

[Krulligo]

Just for anyone that is following, day 4 of SLAM and and 24/7 filtering and constant brushing and pool is at 95-97% clarity compared to the crystal clear water I had before. Sand is working but much slower than expected. Past 3 nights now I have passed OCLT.

What I did find helpful was after the first day of slam, I left the pump off overnight to allow the dead algae to settle to the bottom. Then vacuumed as much to waste as possible. I think without this, it feels like I would be clearing the pool for another week. What I also think was helpful in clearing out the dead algae dust was I double layered hair nets that I use for the skimmer basket. After 24 hours, the hairnets would be quite green/brown so I think a lot of the dust was being caught by the hair nets in addition to the sand filter.

Anyway, planning on dropping down the chlorine to max range for what my CYA was. Will need to rebalance CYA and other chemicals as I did a slight exchange of water due to vacuum to waste and the fact that this all started from an overnight storm where we got lots of rain water. Will start heating the pool back up and running pump at a more normal cycle, hopefully will be swimming again in the next few days.

 

[duraleigh]

The SLAM article has three criteria to define that you have completed it......
Pass OCLT - Yes!
Crystal Clear Water - not quite
No visible sign of algae anywhere in your pool - ??????

YOu should stay at SLAM value until those three things are accomplished

 

[Krulligo]

The SLAM article has three criteria to define that you have completed it......
Pass OCLT - Yes!
Crystal Clear Water - not quite
No visible sign of algae anywhere in your pool - ??????

YOu should stay at SLAM value until those three things are accomplished

Ok I will hold slam for an extra day or 2 hopefully by then it will crystal clear the water. The only visible signs of algae (or what I think is algae dust) was when I checked the hair net in the skimmer basket this morning, it had a hint of green from what I suspect was the residual dead algae dust getting caught on it. Everywhere else the pool is clean, but as I mentioned above, water is clear but just a tad duller than what I remember it being.

 

[Krulligo]

So this morning water is back to looking crystal clear. Actually not much dead algae dust was caught in the double layered hairnets, and I did not see any accumulation in the middle of the pool where debris tend to pool. I think I have finally completed the SLAM so will let the chlorine level drop back down today.

One question is, should I backwash my filter now after SLAM? It has only gone up by ~1 PSI (from 12 to 13). It's not at the 25% range as suggested on here.

 

[wireform]

Take your pool brush drop it carefully down to the pool floor, wait for the water to settle and give it a good push. Watch carefully if you observe a cloud of algae dust while doing it then you'll know your done or not.

 

[Newdude]

be more diligent in keeping chlorine up especially when alot of rain is expected,

If you got a 4 inch storm, which would be a whopper and rare, it would only be about 10% of your pool volume and dilute your FC by the same.

At that point, the rain wasn't the problem, the fact that you were so close to minimum FC was the problem.

Also, when you have bigger storms, do your best to mix it at your earliest convenience, or even better, just turn the pool on when you know it's coming. When 0 FC rain water sits on top festering for up to 16 hours until the pump kicks back on, stagnant water can do a number on the pool. It doesn't take long to get nasty and over the course of the season, could bite you a couple of times.

Always leave wiggle room FC for this or a particularly high UV day, and keep it well mixed. Above ground pools are disadvantaged for circulation from the get go.