Fighting Algae / Balanced Chemicals

[mdchristopher]

Good afternoon. Unfortunately I'm back for additional guidance. We've been fighting algae pockets in the corners/steps/wall surfaces for several weeks. The pool water is clear besides the green/yellow I see on the various surfaces. It's not all over the pool surface (Pebble Finish), just select areas. I've been brushing the areas daily and keeping the chlorine levels elevated. I even did a SLAM for a week keeping the chlorine numbers up around 20. I did the drop test and passed. However, a few days go by and the green starts coming back. We had issues with CYA being elevated at the beginning of the summer and did a complete drain/refill.

A second issue that I've been managing by scrubbing with muriatic acid periodically is calcium build-up on the tiles at the hot tub spill over. Any guidance on keeping this from build-up?

Pool Specs:
15,000 gallon
D.E. Filter
Temp. = 83
pH = 7.7
FC = 8.5 (Hasn't been below 5 for months)
CC = 0
TC = 8.5
TA = 90
CH = 500
CYA = 60
CSI = 0.30

TF-100 Test Kit Utilized

Chemicals Used: Liquid Chlorine 10%
Muriatic Acid 14.5%
D.E. backwash/swap monthly

Guidance/suggestions are greatly appreciated.

 

[mknauss]

When you did the SLAM Process, were all three criteria passed? No visible algae, debris, or cloudy water?

 

[mdchristopher]

Yes sir. It's been a few weeks since the last SLAM. We've never had cloudy water. We can always see the bottom/pebbles in good clarity. We don't have major debris, but the occasional leaf or grass clippings from mowing. No algae present when we completed/stopped the SLAM process. I bumped FC to 22 last week and kept there for 4 days. I let it drift down to 14 for a couple days, then 11. Today's 8.5 is the lowest it's been for a couple weeks.

 

[mdchristopher]

Also, we have a VS pump that runs 24/7. I recently adjusted the settings some to move more water around. 2,000 RPM on low and 3,350 RPM on high. High is from 2-9 PM and Low the remaining hours.

 

[mknauss]

I doubt you need to run the pump at that high of a rate. I would suggest lowering the max rate to 2750 rpm.

I also assume you brush the entire pool at least weekly? Checked all typical hiding places like light niche, skimmer throat/door, ladders, etc.

 

[mdchristopher]

Pump is on high so apologies for the waves.
Deep end view (6’-0”)

 

[mknauss]

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[mdchristopher]

Yes, brush with a pole attachment minimum weekly and even purchased some brushes for the tile and spent a day going around the pool walls/lights/skimmer/etc. brushing vigorously by hand. (Took awhile holding my breath.) I have not removed the lights, but brushed all around and had goggles looking at edges and didn't see anything noticeable. I will say when I backwash/replace D.E. at the first of the month I noticed the water is dingy (brown/green) on the initial flush. Could I have some remnants in the pipes/filters that are causing grief?
I recently went to the bottom of the deep end and saw some green/yellow in the drain under the protective cover. Could that little bit be causing me the grief? I'll need to go down with a screwdriver and attempt to remove without draining the pool to brush in the drain pipe.
No visible algae at the pump when I clean that basket.

 

[mdchristopher]

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[mknauss]

The drain cover algae may lead to these issues.

I would try attaching (with zip ties?) a hose with nozzle attachment to my skimmer pole and try to blow out the stuff under the cover. Really disturbing it and raising your FC to SLAM level may just get it.

 

[mdchristopher]

The drain cover algae may lead to these issues.

I would try attaching (with zip ties?) a hose with nozzle attachment to my skimmer pole and try to blow out the stuff under the cover. Really disturbing it and raising your FC to SLAM level may just get it.

Thanks, I'll give that a shot. Didn't consider taking an air hose down to blow it out vs. trying to remove the cover.

 

[mknauss]

Air or water. Water might be easier to control.

 

[Rancho Cost-a-Lotta]

There have been a lot of similar posts recently...great chemistry, FC above minimum, clear water, no CCs, no unreasonable FC loss, then green/yellow algae on the walls. It happened to me a couple weeks ago. I had my solar cover on for a few days while temps were over 100. Big mistake. I'll let @mknauss advise, but it may be a good idea to follow up the SLAM with the mustard algae procedure:

Mustard Algae

Today We are going to show you how you can get rid of mustard algae in your pool. By following the steps in this guide and with no expensive chemicals.

www.troublefreepool.com

Best of luck!