Acid wash

[sbhuta]

Hello ,

I am planning to drain my pool and wanted to acid wash as I noticed a black - green line around the rim. I have read that acid wash takes years out of your pool. Should I acid wash the pool?
Thank you

 

[Texas Splash]

To help us with your question, lets confirm the following:
- Your pool type? Your profile shows FG but your signature shows pebble. Please confirm which is correct.
- What, if anything, have you attempted to-date to remove this discoloration?
- It's only around the waterline?
- Please post a full set of test results

That should help us to get you a good answer.

 

[sbhuta]

Apologies. Just updated my signature. The profile section does not have an option to choose Pebble Tech

CYA = Above 100
PH = 7.1
FC = 2
TA = 90

It is around the waterline of both SPA and Pool. We just moved into this house so we have not done anything else.

 

[Texas Splash]

Your initial test results tell quite a story. The CYA is extremely high and the FC too low for that CYA (see FC/CYA Levels). In addition, your pH is a bit low (not related to the discoloration) which indicates excessive acid. The high CYA and low pH would indicate the use of chlorine tabs. Is that correct?

 

[Texas Splash]

Actually, since you just moved in, you may not know the entire chlorination history of the pool. But if the tab feeder is full, that's what they used before. So here's some more info:
1. Acid wash? Yes, it does strip some plaster off and reduces the life expectancy. Do you know how old the pool is? Does the surface look solid or worn? Calcium streaks or stains? If you don't "have" to drain it, I probably wouldn't, but sometimes you have no choice.
2. At the same time, you do have to lower the CYA, and the only way to do that is by exchanging some water - probably quite a bit. As an example, if you exchange 50% of your water, it should lower the CYA by 50%.
3. Once you lower the CYA to something between 40-60 (ideally for now), then we would evaluate if you have algae (cloudiness, spotting, green, etc). If you do, then a SLAM Process would be in order. If the water looks crystal clear and you do not suspect algae visually, you could do an Overnight Chlorine Loss Test as a tool to confirm.

Does that help you with your options or concerns?

 

[sbhuta]

1. Pool was put in around 90s.
2. The surface looks solid but I do need to install anti-vortex drain covers(Recommended by the pool inspection at the time of sale), there is a stain on the pool, that I would like to get removed
3. Calcium streaks and also there is some brown stains around the pool
4. The SPA light is gone, so I need to fix that too

But I think I have the information I need.

 

[Texas Splash]

Pics don't look too bad, but I'm sure you see it much better on your end. This is certainly the time of year for you to change water as needed. Good luck and let us know if you have any other questions about the wash, staining (organic or calcium), or anything else. Good luck!

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[proavia]

What is the CH level in your pool? If it hasn't been drained in a few years, it's probably pretty high and a full drain/refill might be best. Check with the city to seewhere youare allowed to drain the water to.

It sounds like you might have a bit of algae at the waterline. When you drain, you can apply some liquid chlorine using a spray bottle to the waterline, scrub it with a scrub brush and rinse it off .... wear old clothes as you will likely get chlorine on them and get bleach spotting on them.

Since your FC has been too low for your CYA level, you may have to do a short SLAM after refilling.