Drained Due to CH Pushing 1000ppm..

ShallowWater

Well-known member
May 8, 2020
482
Riverside, Ca
Pool Size
11000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
IMG_6788.jpegI drained for a refill to get CH under control as it was steadily rising since initial fill in November 2022. Before refilling I want to do a "mild" acid wash myself. Thinking 10:1 MA with a Stainless Steel brush. Thoughts?
 
Last edited:
  • Love
Reactions: Leebo
What are you trying to accomplish with an acid wash?
An acid wash will remove some of the plaster surface, reduce the longevity of your plaster finish and possibly make the surface rougher.

Is there calcium scale buildup at the waterline? If so, consider having that removed by a professional.

Any chance you can install a water softener and plumb it to your autofill?
Using soft water will limit CH rise.
 
The pool has scaled and feels like sandpaper and also exhibits bluing of the white plaster.

Build up on the waterline is minimal as we've removed it each year and it's only been two years.

It is plumbed to a water softener which was broken for a time last year unbeknownst to us.

I think the rise is somehow related to the curing of new shotcrete and plaster as it continued to rise after the water softener was fixed.
 
Your CH and CSI has been consistently high.

You have three ways of handling scale:
  • Run your water chemistry at a low CSI of around -0.6 or even a bit below and it may melt the scale off over a few months. This is the least damaging to your plaster finish but will take the longest.
  • Drain the pool and sanding the plaster using diamond sanding pads with power sanders.
  • Do an acid wash of the pool that will remove the scale but also etch the plaster, remove a layer of it, and weaken the plaster.
 
Last edited:
  • Like
Reactions: KJB1
Based on your PoolMath logs, you need to focus on keeping your pH and TA in check.
If you were to do an acid wash and continue to allow the large pH and TA swings, you will encounter the same issues again.

Looking at you most recent PoolMath log from 5 months ago, it isn't really possible to have a TA of 30 and a pH of 8.5. How did you accurately measure a pH of 8.5. Also, with FC greater than 10, your pH will usually show higher than it actually is.

Review the extended test kit directions. Be sure to take the TA and CH tests to their endpoints.
Many stop adding dropss on the TA and CH tests before the endpoint is actually reached.

If this was my pool, I'd choose option one of the three that @PoolStored posted in post #4 - and I'd test more often, focusing on keeping the pool closely aligned with TFP recommended levels.
 
  • Like
Reactions: ShallowWater
Polishing the plaster to get rid of the roughness is better than acid.



A member used the Stadea SPW104A Concrete Countertop Wet Polisher Grinder with SHDIATOOL 5 Inch Dry Diamond Polishing Pads Grit 50 to remove calcium scale and smooth his plaster.

DRP Tools describes How To Fix (Resurface) Rough Pool Plaster. They sell the diamond polishing pads needed. They also have a Pool Plaster Stain Remover Block to hand sand and remove stains. And they have plaster application tools.

Coyote Abrasives sells the Red Coyote Hydrotorque Pool Plaster Polisher as well as a selection of diamond grit pads and hand polishing pads.
 
Your CH and CSI has been consistently high.

You have three ways of handling scale:
  • Run your water chemistry at a low CSI of around -0.6 or even a bit below and it may melt the scale off over a few months. This is the least damaging to your plaster finish but will take the longest.
  • Drain the pool and sanding the plaster using diamond sanding pads with power sanders.
  • Do an acid wash of the pool that will remove the scale but also etch the plaster, remove a layer of it, and weaken the plaster.
I've been trying to push CSI below -0.3 for a long time but it ended up taking copious amounts of acid. I've now drained the pool because I know it's the only way to get the CH under control and suppose I'll do diamond sanding first. Need to get the pads and sander I suppose.
How to test for sulfates if the scaling is calcium sulfate and doesn't react to acid?
If using diluted MA will it cause as much damage to the plaster?
Based on your PoolMath logs, you need to focus on keeping your pH and TA in check.
If you were to do an acid wash and continue to allow the large pH and TA swings, you will encounter the same issues again.

Looking at you most recent PoolMath log from 5 months ago, it isn't really possible to have a TA of 30 and a pH of 8.5. How did you accurately measure a pH of 8.5. Also, with FC greater than 10, your pH will usually show higher than it actually is.

Review the extended test kit directions. Be sure to take the TA and CH tests to their endpoints.
Many stop adding dropss on the TA and CH tests before the endpoint is actually reached.

If this was my pool, I'd choose option one of the three that @PoolStored posted in post #4 - and I'd test more often, focusing on keeping the pool closely aligned with TFP recommended levels.
I've been struggling since day one to keep pH down and have been pretty successful at keeping TA in line. As far as measuring pH, I use drop titration and when it's purple I call it 8.5 but maybe it's lower. I'll work on keeping the FC lower than 10, preferably around 6 to 8 with CyA at 80 in a salt water chlorinated pool but prefer it nearer 0.1 times the CyA value than 0.075 times the CyA value but am probably overdoing it.

The "sandpaper" seems to come off with light scraping of my fingernail so I'll remove as much as possible before refilling the pool to give it a head start but I don't have enough fingernails to do the whole pool! LOL.

BTW, I don't log every single test so I've tested more recently than last October. My chemistry class always taught first color change when doing titration testing. Is that wrong?
 
Polishing the plaster to get rid of the roughness is better than acid.



A member used the Stadea SPW104A Concrete Countertop Wet Polisher Grinder with SHDIATOOL 5 Inch Dry Diamond Polishing Pads Grit 50 to remove calcium scale and smooth his plaster.

DRP Tools describes How To Fix (Resurface) Rough Pool Plaster. They sell the diamond polishing pads needed. They also have a Pool Plaster Stain Remover Block to hand sand and remove stains. And they have plaster application tools.

Coyote Abrasives sells the Red Coyote Hydrotorque Pool Plaster Polisher as well as a selection of diamond grit pads and hand polishing pads.
Looking to get this one because it will be here tomorrow instead of Thursday.. Our pool is smallish so hopefully it doesn't take too long because its warming up around here!
 
Looking to get this one because it will be here tomorrow instead of Thursday.. Our pool is smallish so hopefully it doesn't take too long because its warming up around here!
Let us know how it works out. The 4” head is small and will take more work.
 

Enjoying this content?

Support TFP with a donation.

Give Support
Let us know how it works out. The 4” head is small and will take more work.
Good point on the head size. I'll keep looking!

BTW, I mentioned "Bluing" of the plaster. I do not use algaecide and the only copper piping is right where the connection is to the water softener. The heater is titanium for salt water chlorination. I believe this to be calcification and not copper staining as it occurs mostly under the spa overflow and the waterfall but does occur in random other locations.

Thoughts?
 
My chemistry class always taught first color change when doing titration testing. Is that wrong?
Yes it’s wrong. Just follow the directions. You generally keep adding drops until the color stops changing. The salt test is a bit different, but read the actual directions in the TF-pro or Taylor kits to get exact process. That may be why your TA comes in so low.
 
Good point on the head size. I'll keep looking!

BTW, I mentioned "Bluing" of the plaster. I do not use algaecide and the only copper piping is right where the connection is to the water softener. The heater is titanium for salt water chlorination. I believe this to be calcification and not copper staining as it occurs mostly under the spa overflow and the waterfall but does occur in random other locations.

Thoughts?
MasterTemp 400 in your signature has a copper heat exchanger, not titanium.

Turquoise stains can be cooper or other metals.
 
MasterTemp 400 in your signature has a copper heat exchanger, not titanium.

Turquoise stains can be cooper or other metals.
I was wrong there but I still don't think the bluing is from copper but could be wrong. It is mainly at locations where there is aeration but does occur in a few other spots. Not sure if they're visible in my picture but I can post more.
 
I was wrong there but I still don't think the bluing is from copper but could be wrong. It is mainly at locations where there is aeration but does occur in a few other spots. Not sure if they're visible in my picture but I can post more.
If you had water in the pool I would recommend you use…


I am not sure how well it will work on the drained surfaces.

The polishing should remove the stains anyway.
 
  • Like
Reactions: ShallowWater
Got the polisher today and tested it out. Works pretty good and cuts the roughness off pretty quickly. I figure it'll take a couple of days to do the whole pool then we'll pump out all the water at the very bottom and use a wet-vac to get everything out. Don't want to start with any of the calcium carbonate from the shell in the water. I'll be pulling a fill water sample soon to get prepped on balancing the pool. I don't think I need to worry about adding salt right away because this is not a new build or re-plaster but could be wrong.

For the experts here.. Should I post fill water results in this thread or start a new thread?
 
Should I post fill water results in this thread or start a new thread?
Keep it here, we'll watch for you!

I don't think I need to worry about adding salt right away because this is not a new build or re-plaster but could be wrong.
Not sure why you wouldn't want to add salt right away to get your SWG going...
When you add salt, leave the SWG off for 24 hours after adding salt.
 
  • Like
Reactions: ShallowWater

Enjoying this content?

Support TFP with a donation.

Give Support