Tiny amount of algae stuck to wall

Mar 21, 2017
11
Los Angeles, CA
Hello... First post here, not sure if this should go into the 'just getting started' section or here.

Long story short: after using a pool company and then a solo 'pool guy', and being burned by them both, I decided to take over and start caring for my pool myself. I've watched a lot of videos and found this forum and am excited to learn more.

We decided to move on from our pool guy because he didn't show up for a few weeks and our water started to turn that greenish hue, we knew where this was going, that was why we left the pool company, they let our pool turn dark green and get just nasty.

So we let the guy go, and I went to work looking online... When the old pool guy showed up, he kept the pool looking great, so I figured that since I was taking action just as the pool started to turn color, we could get it back to blue water just by adjusting FC and pH.

Went to the pool store, got a Poolmaster 22260 5-Way test kit, Liquid chlorine, and Muriatic Acid. Adjusted the pH for the 20,000 gallon pool (I think that's what it is, still trying to determine, but by the amount I was able to lower pH, I think that's the right ballpark), and then added twice the liquid chlorine that was called for. Since the green color of the pool had just started to creep in, and just a small 5-6 foot patch of algae started to form, I thought that shocking the pool might not be needed, and just a little extra chlorine combined with me scrubbing it with a brush, I could get rid of it.

Well, by the next morning, the water was clear as can be, and the small section of algae had faded considerably. I was thinking 'I'm on the right path!'... I figured that maybe if I scrubbed the wall again, while the FC was high, it might keep dissipating, which it did. But only to a point. Now, the water is still clear, but the small patch of algae is still there, and scrubbing it with a nylon scrub brush on a pole has stopped cleaning the area.

So, after all of this, my question is: Should I do what I did before and add a double dose of chlorine, and continue in this fashion until the small remaining line of algae is scrubbed away... Or am I wasting time and money, and I should immediately proceed to shocking the pool (I'm thinking that is the correct answer).

I don't have my readings from the first time I tested the water, but I see on the forums that you guys want to have that... I will provide in the future accurate readings. What I remember though (and I only tested Chlorine and pH). The chlorine was so low that it was 'off the chart' on the test kit color tiles... it had no yellow in it at all. The pH was high, and adding 4 pints (after doing the acid demand test) of Muriatic Acid got me to the 'ideal' mark. I know I need to test my CYA (after doing additional reading on this site), but I don't have that kit yet.


Thanks in advance, and sorry if this is a bit long and rambling! Just getting started with the pool, hoping I'm not screwing it up too much already!



No signature yet... Work in progress... But the pool is an in-ground pool with attached spa. I believe it is 20-22,500 gallons. Will add more info about equipment soon.
 
Hello and welcome to TFP! :wave: You're correct about one thing - any algae requires the FC level to be increased. For that, we at TFP deploy the "SLAM" approach (link in my sig below). But before starting the SLAM, it's critical to validate your CYA level so you know "exactly" how much bleach to add to increase FC to the proper SLAM Shock/SLAM level. I'm not familiar with the Poolmaster tester you are using as we recommend either the TF-100 or Taylor K-2006C, but if your tester can give you an accurate CYA, then you can refer to the Chlorine/CYA Chart (link below) and increase FC to the appropriate level. As noted on the SLAM page, make sure to maintain the FC SLAM/Shock level until you pass all 3 criteria.

As for that one stubborn area, it could be an organic stain that just needs more time to finally fade away. Gently rubbing a chlorine tablet on it might show some quick fading could confirm it's an organic stain that could fade in time with the proper FC/CYA level. Hope that helps. Let us know if you still have questions. Nice to have you with us.
 
Thanks for the reply!

In my haste to get things moving, because I don't want the pool to take too long, I went and bought another test kit (the store didn't have the recommended one, but it did test for CYA). I got a HTH 6 WAY TEST KIT. For the Chlorine and Bromine tests, the color chart only goes up to 5 and 10, and the pH goes from 6.8 - 8.2

My results are as follows:
Chlorine 5+ Judging by the color, if the chart continues I'd imagine it would be a 7-8
Bromine 10+ (same as above, estimating 16-20)
pH 7.3
Total Alkalinity 100
Total Hardness Test did not render RED.
CYA 100+ (200)

The CYA test was in its own vial, and I mixed the solution as recommended, then slowly dropped into the view tube until the black dot at the bottom disappeared. The view tube only measures from 100 down to 30 (if filled to the top). So again, based on the logarithmic way the numbers are painted on the tube, I would estimate CYA to be 200. I was afraid of this, as I have been reading about the pucks, and how they add CYA to the pool. The last pool guy used liquid chlorine or bleach, but the pool company we used before them used the puck in the floating thing. Also, the couple we bought the house from last year also used the same pool company, so they have been throwing pucks in there for years potentially.

So now, my question is, should I SLAM the water, then deal with the CYA, or drain my pool and refill first, then SLAM it all? That sounds more likely the right answer. Is there any way to tell how much of the pool I'd need to drain?

Also... I'll need to figure out how to drain the pool! Any recommendations for videos or guides or should I just start youtubing the scenario.

Thanks a lot for the reply... looking forward to getting this pool under control!!!

Hello and welcome to TFP! :wave: You're correct about one thing - any algae requires the FC level to be increased. For that, we at TFP deploy the "SLAM" approach (link in my sig below). But before starting the SLAM, it's critical to validate your CYA level so you know "exactly" how much bleach to add to increase FC to the proper SLAM Shock/SLAM level. I'm not familiar with the Poolmaster tester you are using as we recommend either the TF-100 or Taylor K-2006C, but if your tester can give you an accurate CYA, then you can refer to the Chlorine/CYA Chart (link below) and increase FC to the appropriate level. As noted on the SLAM page, make sure to maintain the FC SLAM/Shock level until you pass all 3 criteria.

As for that one stubborn area, it could be an organic stain that just needs more time to finally fade away. Gently rubbing a chlorine tablet on it might show some quick fading could confirm it's an organic stain that could fade in time with the proper FC/CYA level. Hope that helps. Let us know if you still have questions. Nice to have you with us.

- - - Updated - - -

New question:

I live in southern CA, when the summer hits, I'll be adding water to the pool about 2-3 times per week due to evaporation. Could that work for 'refilling' the pool... Obviously it will take longer, but if that is a viable option, perhaps I'd consider that.

Reading another post on the forum answered this one! This site is awesome.
 
Simpleman, you need TF-100 and can obtain one pretty fast from Pool Supplies, Spa Supplies and Parts there in California. They're your fastest bet.

To raise FC to SLAM level you *need* the FAS-DPD chlorine test which read up to 50ppm. The TF-100 contains that.

I'd suggest ordering it tonight! Tossing in a SpeedStir device just makes testing faster and even more reliable.

Yip :flower:
 
For testing the CYA you can mix a solution of 1/2 tap water and 1/2 Pool water and then test as before. When you get the number on the black dot dissaperance then double that number for your true CYA instead of an estimate.
Based on what you have said you will likely need to change out at least some of your water (unless you live somewhere where cost of the ever precious water is less expensive than a reverse osmosis on wheels treatment). You can drain all the water, but you have to be cautious if you have a high water table as you can float aka pop the pool.
Depending on where the stain is you might be able to use a pressure washer on it to clean it off while you have the water drained. I have had luck in my pool with a pressure washer and a turbo nozzle even with the pool full, though I had to get real close to get it (black algae on the walls in my case, leftover from my swamp days). Word of warning I did have a few patches of plaster pop off, but that might be a direct result of the swamp era neglect too.
Pictures of the pump and filter area would be useful for directing you how to drain the pool. In general you want to be pulling just from the main drain and then open a valve or series of valves that go to an open section of pipe, possibly with a blue discharge hose on it.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 
So, now that I know I'll need to drain the pool, and pool math says I'll need to get rid of about 80% of the water, do I need to worry about the pool popping out?

It is an in-ground plaster pool, built in roughly 1994.

Or is this the type of thing where I just have to start draining and then take it from there... whatever damage is done, fix it then?
 
It depends on groundwater level. The safe bet is to drain to 1 foot left in the shallow end and do it over several cycles if you are unsure.

Which test kit did you decide on getting?
 
Updated CYA using this 1/2 pool and 1/2 tap water method. I get just over 100, about 1 or 2 drops away from 100. So that puts my CYA at just over 200.

Pool math says 85% of the water needs to be replaced. Is it safer for me to do about 25% of the water, and do that process a few times until my levels are under control?

I am worried because the house and pool is at the top of a hill, and the pool is on the hillside... Don't want to have structural integrity problems on a hillside!



For testing the CYA you can mix a solution of 1/2 tap water and 1/2 Pool water and then test as before. When you get the number on the black dot dissaperance then double that number for your true CYA instead of an estimate.
Based on what you have said you will likely need to change out at least some of your water (unless you live somewhere where cost of the ever precious water is less expensive than a reverse osmosis on wheels treatment). You can drain all the water, but you have to be cautious if you have a high water table as you can float aka pop the pool.
Depending on where the stain is you might be able to use a pressure washer on it to clean it off while you have the water drained. I have had luck in my pool with a pressure washer and a turbo nozzle even with the pool full, though I had to get real close to get it (black algae on the walls in my case, leftover from my swamp days). Word of warning I did have a few patches of plaster pop off, but that might be a direct result of the swamp era neglect too.
Pictures of the pump and filter area would be useful for directing you how to drain the pool. In general you want to be pulling just from the main drain and then open a valve or series of valves that go to an open section of pipe, possibly with a blue discharge hose on it.

Sent from my SAMSUNG-SM-G930A using Tapatalk

- - - Updated - - -

I picked up the HTH 6 way test kit at the store... Am going to be ordering one of the recommended kits soon.


It depends on groundwater level. The safe bet is to drain to 1 foot left in the shallow end and do it over several cycles if you are unsure.

Which test kit did you decide on getting?
 

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While an 85% water exchange may be best and the most efficient, if you have any doubt about the soil integrity, then perhaps consider exchanging about half, then maybe doing that again after refilling? It's not as efficient, but perhaps best to be safe. For what it's worth, once the CYA is back down to earth (70 or below), then you will be able to manage your pool much more efficiently. In addition, the CYA will never increase again unless you chose to raise it on purpose. Just make sure to never add stabilizer/condition or products that use stabilizer (i.e. chlorine tabs/pucks, bags of shock, etc) from the pool store. Stick just to "regular" liquid bleach, and make sure it's plain - no scented or splashless bleach.

No need to start the SLAM until you exchange the water then have the proper test kit so you can test FC at levels 10 or more. If you order the TF-100, I would recommend the XL option for more reagents, and also recommend the magnetic speedstir which helps tremendously with stirring. If you chose the Taylor K-2006, make sure to get the 2006 "C" which has more reagents. I can confirm the TF-100 is a fantastic bargain and you won't be disappointed.

Good luck and keep us posted.
 
Lowered the pool level quite a bit, but not all the way because of safety concerns. Refilled and let the filter mix the water all night. This morning my CYA is just barely more than the 100 mark, I believe it to be around 115-120.

So definitely moving in the right direction, and now that I know how to do everything, I'm gonna get the pool draining now and will do another refill. Once refilled, how long should I let the filter run before I can test for CYA, or should I just let it sit overnight again?
 
After a second partial drain and refill, then letting the filter run all night, here are my updated numbers:

FC - 10
pH - 7.6
TA - 170
CYA - 75 (awesome!)

A few observations: With the FC still being so high, but the CYA level drastically reducing over the course of two days, the algae I mentioned in my first post has all but dissipated on its own, overnight. I'm guessing it's because now that the CYA isn't reducing the effectiveness of the chorine, it can do its job. SCIENCE!!!

My TA went up by 70 over the two days, is that something I should manage back down or will it drift down with use and maintenance?

I will now begin the process of SLAM-ing my pool. I'll post a few pictures along the way. I never really thought the water looked very cloudy before, but my wife mentioned to me that she's never seen the water look so nice, and I have to agree!


Thanks for all the help, everyone! This site rules.
 
Great news! Yes, I agree that the lower CYA is allowing the FC to be more potent and work in balance as they should together. Your TA probably shot-up form the new fill water. You can easily lower that later after the SLAM once you pass all 3 SLAM criteria. Do that first, then take a look at the TFP Pool School - Lower Total Alkalinity.

Have a nice weekend!

PS - Don't forget to lower your pH to about 7.2 before starting the SLAM! :)
 
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