Green/brownish layer bottom of pool

[fhorta]

Hello all. I cannot get rid of fine layer of what i think is dead algae on inground pool. About 25k gallons. Have a sta rite 3 sand filter. Plaster/gunite, not really sure if there is any difference.

I have tried raising chlorine level to 10 ppm but not clearing. I haven't really held it there consecutive days, i think i did hold it at 6 ppm two days in a row. I use liquid chlorine, 12%.

Pump has been on for a week 24/7 now and not letting up. I will add some DE periodically. The pump gauge does go up to 14, 15 pressure and I back wash. Green Crud comes out. I keep filtering but that stuff still there.

I tried vacuuming to waste. But my system don't have vacuum to waste setting. So i just set it to backwash and manually vacuum. I did that yesterday but this morning floor still the same. After vacuuming, I raised chlorine to 12ppm last night and this morning still about the same chlorine. Floor still same.

I had water tested and was told combined chlorine is about 2.5ppm and i needed to throw in all 4 gallons of chlorine to shock pool. I told lady already at 12ppm and she said its not the ppm, its about how many gallons you throw in???

I have 4 lbs of potassium chloride oxidizer i plan on throwing in tonight. Any ideas, suggestions??Also, plan on changing sand. Its about 9 years old.

Additional info, sorry forgot. CYA is about 25 to 30. I know i neeed to raise it but wanted to clear this stuff first.
Alk is 100
Hardness is 200
Ph before adding chlorine was 7.4-7.6 range. Today is above 8 probly due to high chlorine.
Filter gauge reads 9 psi on fresh backwash. Right now its about 10 psi.
I use the Taylor 2006 test kit.

 

[mknauss]

You need to follow the SLAM Process.

Do not use non chlorine shock. It will mess up your CC testing for some time.

 

[PoolStored]

After vacuuming, I raised chlorine to 12ppm last night and this morning still about the same chlorine. Floor still same.

Ph before adding chlorine was 7.4-7.6 range. Today is above 8 probly due to high chlorine.

pH test is invalid above 10 FC. Your pH is likely still 7.4-7.6.

 

[fhorta]

Thanks. I will follow slam process. With regards to vaccuming to waste, your opinion on vaccuming in backwash mode to waste? I know vacuuming to waste purpose is to bypass flter altogether, but you think would still accomplish goal? Is there another method to use to vacuum to waste when there is no setting for that?

 

[fhorta]

I heard of a technique to make a slide valve vacuum to waste. Has to do with taking out plunger and sticking in an expansion rubber, basically keeping water going into filter and straight out to waste....any opinions?

 

[fhorta]

Update, been slamming, changed sand, added DE and still no improvement since Saturday. I think I will try some skill it. Just pour whole bottle. It's worked before. I just don't see why it's not clearing and why skill it would fix problem. I have polyquat algaecide, but dint want to use that until I have clear floor and water. Thoughts?

 

[fhorta]

Also , considering maybe increasing chlorine? Maybe 12 ppm not enough. Right now pressure gauge at 13 psi. Clean pressure is 9. Water coming out of jet returns still feels decent, don't thunk I should backwash yet. I am losing 2 ppm chlorine over night.

 

[PoolStored]

Also , considering maybe increasing chlorine? Maybe 12 ppm not enough. Right now pressure gauge at 13 psi. Clean pressure is 9. Water coming out of jet returns still feels decent, don't thunk I should backwash yet. I am losing 2 ppm chlorine over night.

Anything more than an FC level of 12 is a waste and will burn off. If your normal pressure is 9, then you should backwash when your pressure rises 25%. That means backwash when it hits 11.

 

[fhorta]

At 11? Forgot to mention I added DE and got pressure to 10 ppm. Would that change when to backwash? Also, my diverter has 3 settings; skim only, pull water from bottom drain only, or both, bottom and skimmer on top. I have had it on skim only. Should I change to both?

 

[PoolStored]

At 11? Forgot to mention I added DE and got pressure to 10 ppm. Would that change when to backwash? Also, my diverter has 3 settings; skim only, pull water from bottom drain only, or both, bottom and skimmer on top. I have had it on skim only. Should I change to both?

Backwash at 12 with DE. Open the main and slowly brush the algae to the drain. Will help clear it.

 

[fhorta]

Backwash at 12 with DE. Open the main and slowly brush the algae to the drain. Will help clear it.

OK, thanks

 

[fhorta]

Well, couple days, same situation. No change. When backwash, green stuff comes out, but day after day, no change. Can't see the floor clearly and that layer of stuff still there very visible when brush. Last couple nights, not losing any chlorine really. Go to bed at 12ppm or slightly over, and wake up pretty much the same. I think I will just have to drain it and start over. Will 3/4 of the way do, or should I do complete drain?. I will be using submersible pump

 

[PoolStored]

Can you post a picture of the pool?

Can you also fill out your signature like mine below? (if you are on a phone, turn it to landscape). Knowing what kind of pool and equipment you have will really help us help you. Create Your Signature - Further Reading

 

[PoolStored]

Will 3/4 of the way do, or should I do complete drain?. I will be using submersible pump

Let's understand where you are located, type of pool and picture before we do anything. If you are in an area with a high water table and a fiberglass pool, doing a drain migh be a big mistake.

 

[fhorta]

I filled in info. I don't see it on my signature though.

 

[fhorta]

Oh , there it is

 

[IceShadow]

I see your signature.

Have you checked the CYA lately and confirmed it's still in the 30-ish range?

How often are you testing and adding liquid chlorine to increase the FC level back to SLAM level?

DE in the filter is probably not needed if you're still green. Let's kill the algae first. We can still filter it out but it will clog up too fast with DE if it's an active outbreak.

Don't bother with algaecide. It'll eat extra FC and won't do anything during an active outbreak.

I don't know what "Skill-It" is, but I wouldn't add it. We just need to help you make sure you're doing the SLAM properly. It shouldn't take more than a few days to kill off the algae and make it at least a cloudy blue pool if you are SLAMming properly.

 

[fhorta]

Pic from this morning. Actually, have to say slight improvement for first time. I am raising chl to 12 at night and checking in the am before Sun up. I'm only putting in 1/4 cup DE after backwash. Haven't checked cya lately. Checking chl everyday in the evening and morning. Can't wait to get home and see how looks, 9 hours after this morning . Will slam again tonight and hopefully even more improvement in the am. Thanks

 

[fhorta]

Yea, so cya has gone up to about between 40 and 50. Never can tell on cya. Is the dot supposed to completely disappear, or we just look to when dot starts fading away and ALMOST disappears? At any rate, I increased slamming to 20 ppm, maybe 21 last night , and this morning was at 20. I had heard though that anything past 12 is a waste?? The water clarity seems ; I don't know, maybe little improvement. Hard to tell. Wondering if I should go ahead and vacuum, or wait until water is crystal clear first?

 

[fhorta]

Ok, water clarity just around 98% of desired goal. Stuff on bottom nearly invisible now. When i brush this morning, can't see that cloud anymore. Been slamming at 20 overnight. As of this morning, lost about 3 ppm overnight. Should probably keep slamming, right? The filter pressure slightly over 10 psi. 9 psi is when clean. Been at around 10 for last two days. I do have a cotton towel in skimmer basket. When I wash it, pretty green, but less and less more recently.