Dirt or algae?

Nillawafers

Member
May 24, 2019
17
San Gabriel, CA
Water is clear, sparkling even. But I still have tons of gathered "dirt" or algae. I have passed my OCLT, I am wondering if it's fine dirt my filter can't catch?
I have very fine, claylike dirt that is almost hydrophobic at times. I have a cartridge filter.

I feel like I vacuum it up and it's back only an hour later. I don't have an option to vacuum to waste on my pump, but I was thinking I could pull the tube off once I get the vacuum started to keep up a natural gradient? I worry about how much water I will lose though, if it's even possible due to the length of my vacuum hose.

I have to admit I am not good at recording results on the app, but I can promise I've done a 2-3 day shock with no OCL. ?
 

mariane

Bronze Supporter
LifeTime Supporter
May 8, 2012
1,089
Southeast Michigan
Water is clear, sparkling even. But I still have tons of gathered "dirt" or algae. I have passed my OCLT, I am wondering if it's fine dirt my filter can't catch?
I have very fine, claylike dirt that is almost hydrophobic at times. I have a cartridge filter.
If you push to brush towards it and it goes "puff" into a cloud, it is algae. Dirt/debris will resettle right away.
That also means you have not met all the requirements to stop the SLAM. Keep going.
Cartridge filters are better at picking up dirt than sand filters but I'm pretty sure it's algae.
I have to admit I am not good at recording results on the app, but I can promise I've done a 2-3 day shock with no OCL. ?
What are you using to "shock"? What "shock" level are you at?
A SLAM is taking the FC to "shock level and maintain" until, water is crystal clear, no algae, FC loss of <1 and CC <0.5. It has to meet all three. Then do the OCLT.
 

Nillawafers

Member
May 24, 2019
17
San Gabriel, CA
If you push to brush towards it and it goes "puff" into a cloud, it is algae. Dirt/debris will resettle right away.
That also means you have not met all the requirements to stop the SLAM. Keep going.
Cartridge filters are better at picking up dirt than sand filters but I'm pretty sure it's algae.

What are you using to "shock"? What "shock" level are you at?
A SLAM is taking the FC to "shock level and maintain" until, water is crystal clear, no algae, FC loss of <1 and CC <0.5. It has to meet all three. Then do the OCLT.
16 FC. Water is crystal clear. I have around 40 cya in my pool. I am using 10% HDX liquid shock, which from my understanding is just concentrate bleach.

So you're saying as long as it's accumulating on the bottom I shouldnt stop slamming? It's very hard to tell, should I be vacuuming 3 to 4 times a day then? Because as soon as I vacuum it is back a few hours later, so how can I tell when it's done?
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,930
San Dimas, CA (LA County)
16 FC. Water is crystal clear. I have around 40 cya in my pool. I am using 10% HDX liquid shock, which from my understanding is just concentrate bleach.

So you're saying as long as it's accumulating on the bottom I shouldnt stop slamming? It's very hard to tell, should I be vacuuming 3 to 4 times a day then? Because as soon as I vacuum it is back a few hours later, so how can I tell when it's done?
When you've killed it all, it will stop reproducing and it will disappear. It sounds like right now you've got a little bit left and it's growing and dying at the same rate which gives you a neverending supply of dead clumped algae. It resembles underwater dust bunnies.

Common hiding places are inside ladders and beneath steps and behind lights. If the ladder is in the pool, pull it out and look Check out these pictures
 

mariane

Bronze Supporter
LifeTime Supporter
May 8, 2012
1,089
Southeast Michigan
16 FC. Water is crystal clear. I have around 40 cya in my pool. I am using 10% HDX liquid shock, which from my understanding is just concentrate bleach.
Good stuff. That's right.
So you're saying as long as it's accumulating on the bottom I shouldn't stop slamming?
Yes, as long as it's accumulating on the bottom, you need to continue the SLAM.
It's very hard to tell, should I be vacuuming 3 to 4 times a day then? Because as soon as I vacuum it is back a few hours later, so how can I tell when it's done?
Vacuum to the filter the accumulated patches. When it comes back a few hours later it is dieing and dropping to the bottom.
It's done when nothing accumulates on the bottom, the FC holds and no CC.
 

Nillawafers

Member
May 24, 2019
17
San Gabriel, CA
Gotcha. It's a 14 foot vinyl pool, no lights, I'll check the ladder tho. Just added more chemicals this morning and changed the filter. Could I just brush the algae so it gets sucked into the pump? Vacuuming is very time consuming haha.
 

Nillawafers

Member
May 24, 2019
17
San Gabriel, CA
I think I've been slamming for about 5 days now, vacuuming every day, brushing almost everyday. I am still getting spots of algae mounds on the bottom. Is there a way to speed this up? I have noticed a *slight* reduction in the amount, but it feels they appear as soon as an hour after vacuuming? Quite frustrating. Should I be vacuuming more? Could I raise the slam level higher and have it be more effective? I've brushed under the flaps on the side of the pool, and cleaned the ladder (I couldn't see anything growing there anyways).
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,930
San Dimas, CA (LA County)
Raising FC would probably just waste bleach.

I'm wondering of the algae isn't just getting pushed back into suspension rather than being sucked through the filter. You have to be super patient and let the suction pull it in before you advance the vacuum head. Maybe disconnect the vacuum when you're done but leave it in the pool so there's less disturbance then next time you vacuum. Just feed the hose in the water slowly to force the air out and connect and go.
 

aeh0603

Well-known member
Apr 6, 2016
353
San Diego, CA
Is there anywhere else in your pool that algae could be hiding? Behind a light, under drain covers, in the skimmer or behind the weir door, any water features?

No need to go above SLAM level. You risk bleaching your liner and will likely loose most of it to the sun anyway.
 

Nillawafers

Member
May 24, 2019
17
San Gabriel, CA
Is there anywhere else in your pool that algae could be hiding? Behind a light, under drain covers, in the skimmer or behind the weir door, any water features?

No need to go above SLAM level. You risk bleaching your liner and will likely loose most of it to the sun anyway.
No it's a pretty plain Jane pool. I have one plastic return, and two intakes. I do have an attachable skimmer but it looks free of algae.
 

Nillawafers

Member
May 24, 2019
17
San Gabriel, CA
Hi all. It's been a bit but I wanted to share my discovery with anyone who might have had the same problem as me.

I was SLAMing correctly but really using the wrong type of vacuum head to completely vacuum and remove the dead algae. I was originally using an Intex vacuum head that had bristles around the head, this was basically pushing the algae around and not allowing it to be vacuumed up. Meaning it would just stay in the pool and resettle hours later.

I switched to a wedge shaped head (kinda like a squeegee) and now when I have to slam the algae is typically gone in a day.

Just figured I would post so others searching the same problem might find a solution.
 

mariane

Bronze Supporter
LifeTime Supporter
May 8, 2012
1,089
Southeast Michigan
Great that it's working for you. :smile: Yeah, the key is to slowly sneak up on the algae so as not to disperse it before vacuuming it up.
Can you attach a picture of the topside and the underside? I'm trying to picture it.
Thanks.